Dietary Treatment for Overweight and Obesity - How Weight-loss Diets Work

Research demonstrates that weight loss is associated with the length of the diet, pre-diet weight (persons who are more overweight tend to lose more weight, more quickly than those who are only mildly overweight), and the number of calories consumed. Any diet that restricts caloric intake such that calories consumed are less than those expended will promote short-term weight loss. The key to weight loss through diet is adherence—if people do not stick to their diets, then they will not lose weight. As early as the 1860s, William Banting, describing the benefits of his low-carbohydrate diet, wrote that "The great charms and comfort of the system are that its effects are palpable within a week of trial and creates a natural stimulus to persevere for a few weeks more."

The successes achieved using regimens that restrict dieters to a single food or food group such as grapefruits, pineapples, or cabbage are probably in part attributable to the human hankering for variety. Limited to just one food, most dieters experience boredom—there is just no appeal to eating the same food at every meal, for days on end, so naturally, less food is consumed. In addition, these diets generally rely on low-calorie foods, so that even if dieters were inspired to consume ten grapefruits per day, their total daily caloric consumption would be about 1,200 calories, which is sufficient to produce weight loss for most persons who are overweight. Similarly, diets that involve stringent portion control effectively reduce calories to produce weight loss.

Low-Calorie Diets

Traditional dietary therapy for weight loss generally seeks to create a deficit of 500 to 1,000 calories per day with the intent of promoting weight loss of between one to two pounds per week. Low-calorie diets (LCDs) for men usually range from 1,200 to 1,600 calories per day; for women LCDs contain between 1,000 and 1,200 calories per day. Table 5.3 is an example of the recommended percentages of nutrients in an LCD that aims to decrease risk factors for hypertension and high cholesterol as well as cause weight loss.

The most successful LCDs take individual food preferences into account to custom-tailor the diet. Table 5.4 and Table 5.5 show examples of how traditional American cuisine may be used to create a low-calorie diet containing 1,200 and 1,600 calories per day respectively. Table 5.6 incorporates regional Southern cuisine into a reduced-calorie diet. Table 5.7 illustrates how Asian American cuisine FIGURE 5.3
Saturated fat intake as percent of total calories, National Health and Nutrition Examination Survey, 1999–2000 may be adapted to 1,200- and 1,600-calorie-per-day diets, and Table 5.8 shows how Mexican American cuisine may be adapted for low-calorie diets. Table 5.9 is a sample of a reduced-calorie diet that vegetarians who eat milk and eggs but no meat or fish can use to lose weight. Food exchanges, such as those shown in Table 5.10, enable dieters to enjoy a variety of foods in their reduced-calorie meals, which can prevent boredom and the tendency to abandon the diet.

Research reveals that reducing fat in the diet is an effective way to reduce calories, and that when low-calorie diets are combined with low-fat diets, better weight loss is achieved than through calorie reduction alone. Further, while very-low-calorie diets that provide about 500 calories per day have been demonstrated to produce greater initial weight loss than the low-calorie diets, the long-term weight loss is not different between the two regimens.

Low-Carbohydrate Diets

During 2003 several rigorous research studies reported that low-carbohydrate diets were as effective, or even more effective, in producing short-term weight loss than low-fat diets. The low-carbohydrate diets owed much of their success FIGURE 5.4
Dietary cholesterol intake as percent of total calories, National Health and Nutrition Examination Survey, 1999–2000 to adherence—dieters were better able to stick with their diets, and as a result achieved better results. Another hypothesis about the success of low-carbohydrate regimens is that dieters do not feel as hungry as they do on other diets because protein is the most satisfying of the three macronutrients—carbohydrates, fats, and protein.

The scientific premise of low-carbohydrate diets is that consuming certain carbohydrates can cause surges in blood sugar and insulin that not only stimulate appetite and weight gain but also may increase risk for diabetes and heart disease. The earliest low-carbohydrate diets viewed all carbohydrates as equally harmful. Increasingly, however, low-carbohydrate diets distinguished between simple and complex carbohydrates, which contain simple or complex sugars.

Examples of single sugars from foods include fructose, which is found in fruits, and galactose, which is found in milk products. Double sugars include lactose in dairy products, maltose, which is found in certain vegetables and in beer, and sucrose (table sugar). Examples of complex carbohydrates, often referred to as "starches" are breads, cereals, legumes, brown rice, and pastas. Simple carbohydrates occur naturally in fruits, milk products, and vegetables; at the same time, these foods also contain vitamins and minerals. FIGURE 5.5
Dietary sodium intake as percent of total calories, National Health and Nutrition Examination Survey, 1999–2000 The simple carbohydrates most nutritionists call "empty calories" are the processed and refined sugars found in candy, table sugar, and sodas as well as foods such as white flour, sugar, and polished rice (unless they are labeled "enriched" or "fortified" with vitamins or other nutrients).

Low-carbohydrate regimens in the early twenty-first century distinguish between simple and complex carbohydrates and rely on a measure known as the glycemic index (GI), which ranks foods based on how rapidly their consumption raises blood glucose levels. The GI measures how much blood sugar increases over a period of two or three hours after a meal. Carbohydrate foods that break down quickly during digestion have the highest glycemic indices. The GI may be used to determine if a particular food will trigger the problematical "carbohydrate–blood sugar–insulin cascade." High-GI foods are those that are rapidly digested and absorbed or transformed metabolically into glucose. These include refined starchy foods such as bread, cereal, pasta, and table sugar. In general, fiber-rich foods are low glycemic. Most vegetables, legumes, and fruits are low-GI foods.

Measurement of GI is a relatively recent practice. It began during the 1990s, following the discovery that specific carbohydrates such as potatoes and cornflakes raised TABLE 5.3
Low calorie Step 1 diet

Nutrient	Recommended Intake
Calories1	Approximately 500 to 1,000 kcal/day reduction from usual intake
Total fat2	30 percent or less of total calories
Saturated fatty acids3	8 to 10 percent of total calories
Monounsaturated fatty acids	Up to 15 percent of total calories
Polyunsaturated fatty acids	Up to 10 percent of total calories
Cholesterol3	<300 mg/day
Protein4	Approximately 15 percent of total calories
Carbohydrate5	55 percent or more of total calories
Sodium chloride	No more than 100 mmol/day (approximately 2.4 g of sodium or approximately 6 g of sodium chloride)
Calcium6	1,000 to 1,500 mg/day
Fiber5	20 to 30 g/day
1A reduction in calories of 500 to 1,000 kcal/day will help achieve a weight loss of 1 to 2 pounds/week. Alcohol provides unneeded calories and displaces more nutritious foods. Alcohol consumption not only increases the number of calories in a diet but has been associated with obesity in epidemiologic studies as well as in experimental studies. The impact of alcohol calories on a person's overall caloric intake needs to be assessed and appropriately controlled.
2Fat-modified foods may provide a helpful strategy for lowering total fat intake but will only be effective if they are also low in calories and if there is no compensation by calories from other foods.
3Patients with high blood cholesterol levels may need to use the Step II diet to achieve further reductions in LDL-cholesterol levels; in the Step II diet, saturated fats are reduced to less than 7 percent of total calories, and cholesterol levels to less than 200 mg/day. All of the other nutrients are the same as in Step I.
4Protein should be derived from plant sources and lean sources of animal protein.
5Complex carbohydrates from different vegetables, fruits, and whole grains are good sources of vitamins, minerals, and fiber. A diet rich in soluble fiber, including oat bran, legumes, barley, and most fruits and vegetables may be effective in reducing blood cholesterol levels. A diet high in all types of fiber may also aid in weight management by promoting satiety at lower levels of calorie and fat intake. Some authorities recommend 20 to 30 grams of fiber daily, with an upper limit of 35 grams.
6During weight loss, attention should be given to maintaining an adequate intake of vitamins and minerals. Maintenance of the recommended calcium intake of 1,000 to 1,500 mg/day is especially important for women who may be at risk of osteoporosis.
SOURCE: "Table 4. Low Calorie Step I Diet," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

blood sugar faster than others such as brown rice and oatmeal. Harvard University School of Public Health researchers used GI to calculate glycemic load—a measure that considers the food's GI and the amount of carbohydrate contained in a single serving. For example, many whole fruits, vegetables, and grains have low glycemic loads, which when consumed prompt a moderate rise in blood glucose and insulin. When the same fruits, vegetables, and grains are squeezed or pulverized into juice or flour, their glycemic load increases—effectively rendering them with the same high glycemic load of sugar water.

After consuming a meal with a high glycemic load, blood sugar rises higher and faster than it does after eating a meal with a low glycemic load. In an effort to recover from the resulting peaks and plummets, the brain transmits a hunger signal long before the next meal is due. Wildly fluctuating blood sugar and insulin may result in overeating, which in turn causes overweight. For TABLE 5.4
Sample reduced calorie menus, traditional American cuisine—1,200 calories

	Calories	Fat (grams)	% Fat	Exchange for
Breakfast
• Whole wheat bread, 1 medium slice	70	1.2	15	(1 bread/starch)
• Jelly, regular, 2 tsp	30	0	0	(½ fruit)
• Cereal, shredded wheat, ½ cup	104	1	4	(1 bread/starch)
• Milk, 1%, 1 cup	102	3	23	(1 milk)
• Orange juice, ¾ cup	78	0	0	(1 ½ fruit)
• Coffee, regular, 1 cup	5	0	0	(free)
Breakfast total	389	5.2	10
Lunch
• Roast beef sandwich:
Whole wheat bread, 2 medium slices	139	2.4	15	(2 bread/starch)
Lean roast beef, unseasoned, 2 oz	60	1.5	23	(2 lean protein)
Lettuce, 1 leaf	1	0	0
Tomato, 3 medium slices	10	0	0	(1 vegetable)
Mayonnaise, low calorie, 1 tsp	15	1.7	96	(⅓ fat)
• Apple, 1 medium	80	0	0	(1 fruit)
• Water, 1 cup	0	0	0	(free)
Lunch total	305	5.6	16
Dinner
• Salmon, 2 ounces edible	103	5	44	(2 lean protein)
• Vegetable oil, 1 ½ tsp	60	7	100	(1 ½ fat)
• Baked potato, ¾ medium	100	0	0	(1 bread/starch)
• Margarine, 1 tsp	34	4	100	(1 fat)
• Green beans, seasoned, with margarine, ½ cup	52	2	4	(1 vegetable) (½ fat)
• Carrots, seasoned	35	0	0	(1 vegetable)
• White dinner roll, 1 small	70	2	28	(1 bread/starch)
• Iced tea, unsweetened, 1 cup	0	0	0	(free)
• Water, 2 cups	0	0	0	(free)
Dinner total	454	20	39
Snack
• Popcorn, 2 ½ cups	69	0	0	(1 bread/starch)
• Margarine, ¾ tsp	30	3	100	(¾ fat)
Total	1,247	34–36	24–26
Calories…1,247	Saturated fat, % kcals…7
Total carbohydrate, % kcals … 58	Cholesterol, mg … 96
Total fat, % kcals… 26	Protein, % kcals … 19
*Sodium, mg … 1,043
Note: Calories have been rounded.
1,200: 100% RDA met for all nutrients except vitamin E 80%, vitamin B2 96%, vitamin B6 94%, calcium 68%, iron 63%, and zinc 73%.
* No salt added in recipe preparation or as seasoning. Consume at least 32 ounces of water.
SOURCE: "Appendix D. Sample Reduced Calorie Menus: Traditional American Cuisine—1,200 Calories," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

persons who are overweight or physically inactive, another potential danger of consuming foods with high glycemic loads is that they may already be insulin resistant, and overexertion of insulin-producing cells in the pancreas required to metabolize the high glycemic loads may ultimately exhaust their insulin-producing cells, leading to diabetes.

Proponents of low-carbohydrate diets observe that consuming foods with low glycemic loads stabilizes blood sugar and insulin to prevent the fluctuations that can cause overeating and may increase risk for diabetes. They also assert that reliance on low-fat diets inadvertently led to diets that were high in simple carbohydrates, and indirectly promoted the observed increase in overweight and diabetes in the United States.

Low-Fat Diets

Low-fat diets reduce caloric intake by reducing fat consumption. Fat has nine calories per gram, while protein and carbohydrates have four calories per gram. These diets rely on the high-fiber content of complex carbohydrates to satisfy dieters. High-fiber foods also slow absorption of carbohydrates, so they do not provoke a rapid rise in blood sugar and insulin.

Table 5.11 shows some of the food substitutions that may be made to reduce the dietary fat content. In addition to making substitutions, many fat-free or low-fat food products are available—from fat-free frozen desserts to reduced-fat peanut butter. However, dieters are often cautioned that fat-free or reduced-fat foods are not calorie-free, and their consumption will not result in weight loss TABLE 5.5
Sample reduced calorie menus, traditional American cuisine—1,600 calories

	Calories	Fat (grams)	% Fat	Exchange for
Breakfast
• Whole wheat bread, 1 medium slice	70	1.2	15.4	(1 bread/starch)
• Jelly, regular, 2 tsp	30	0	0	(½ fruit)
• Cereal, shredded wheat, 1 cup	207	2	8	(2 bread/starch)
• Milk, 1%, 1 cup	102	3	23	(1 milk)
• Orange juice, ¾ cup	78	0	0	(1 ½ fruit)
• Coffee, regular, 1 cup	5	0	0	(free)
• Milk, 1%, 1 oz	10	0.3	27	(⅛ milk)
Breakfast total	502	6.5	10
Lunch
• Roast beef sandwich: Whole wheat bread, 2 medium slices	139	2.4	15	(2 bread/starch)
Lean roast beef, unseasoned, 2 oz	60	1.5	23	(2 lean protein)
American cheese, lowfat and low sodium, 1 slice, ¾ oz	46	1.8	36	(1 lean protein)
Lettuce, 1 leaf	1	0	0
Tomato, 3 medium slices	10	0	0	(1 vegetable)
Mayonnaise, low calorie, 2 tsp	30	3.3	99	(⅔ fat)
• Apple, 1 medium	80	0	0	(1 fruit)
• Water, 1 cup	0	0	0	(free)
Lunch total	366	9	22
Dinner
• Salmon, 3 ounces edible	155	7	40	(3 lean protein)
• Vegetable oil, 1 ½ tsp	60	7	100	(1 ½ fat)
• Baked potato, ¾ medium	100	0	0	(1 bread/starch)
• Margarine, 1 tsp	34	4	100	(1 fat)
• Green beans, seasoned, with margarine, ½ cup	52	2	4	(1 vegetable) (½ fat)
• Carrots, seasoned, with margarine, ½ cup	52	2	4	(1 vegetable) (½ fat)
• White dinner roll, 1 medium	80	3	33	(1 bread/starch)
• Ice milk, ½ cup	92	3	28	(1 bread/starch) (½ fat)
• Iced tea, unsweetened, 1 cup	0	0	0	(free)
• Water, 2 cups	0	0	0	(free)
Dinner total	625	28	38
Snack
• Popcorn, 2 ½ cups	69	0	0	(1 bread/starch)
• Margarine, ½ tsp	58	6.5	100	(1 ½ fat)
Total	1,613	50	28
Calories … 1,613	Saturated fat, % kcals … 8
Total carbohydrate, % kcals … 55	Cholesterol, mg … 142
Total fat, % kcals … 29	Protein, % kcals … 19
*Sodium, mg … 1,341
Note: Calories have been rounded.
1,600: 100% RDA met for all nutrients except vitamin E 99%, iron 73%, and zinc 91%.
No salt added in recipe preparation or as seasoning. Consume at least 32 ounces of water.
SOURCE: "Appendix D. Sample Reduced Calorie Menus: Traditional American Cuisine—1,600 Calories," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

when more of the reduced-fat foods are consumed than would be eaten of the full-fat versions. For example, eating twice as many baked tortilla chips would actually result in higher caloric intake than a single serving of regular tortilla chips. (See Table 5.12.)

Low-Fat versus Low-Carbohydrate Diets

In the absence of rigorous scientific research and studies demonstrating the long-term safety and effectiveness of low-carbohydrate and low-fat diets, many investigators and health professionals hesitate to proclaim one diet's superiority over all others. There is general consensus that while some diets may produce greater initial weight loss, most perform similarly over time.

In "Efficacy and Safety of Low-Carbohydrate Diets: A Systematic Review" (Journal of the American Medical Association, vol. 289, no. 14, April 2003), Dena Bravata and her colleagues from Stanford and Yale Universities reported the results of their analysis of data about diet-induced changes in weight, serum lipids, fasting serum glucose and fasting serum insulin levels, and blood pressure among adults using low-carbohydrate diets. The investigators stated that they undertook the research in response to concerns about low carbohydrates expressed by the American Dietetic Association (ADA) and the American Heart Association (AHA). Both organizations have warned that low-carbohydrate diets may lead to abnormal metabolic functioning that in turn may prompt TABLE 5.6
Sample reduced calorie menus, Southern cuisine—reduced calorie

	1,600 Calories	1,200 Calories
Breakfast
• Oatmeal, prepared with 1% milk, lowfat	½ cup	½ cup
• Milk, 1%, lowfat	½ cup	½ cup
• English muffin	1 medium	—
• Cream cheese, light, 18% fat	1 T	—
• Orange juice	¾ cup	½ cup
• Coffee	1 cup	1 cup
• Milk, 1%, lowfat	1 oz	1 oz
Lunch
• Baked chicken, without skin	2 oz	2 oz
• Vegetable oil	1 tsp	½ tsp
• Salad:
Lettuce	½ cup	½ cup
Tomato	½ cup	½ cup
Cucumber	½ cup	½ cup
• Oil and vinegar dressing	2 tsp	1 tsp
• White rice	½ cup	¼ cup
• Margarine, diet	½ tsp	½ tsp
• Baking powder biscuit, prepared with vegetable oil	1 small	½ small
• Margarine	1 tsp	1 tsp
• Water	1 cup	1 cup
Dinner
• Lean roast beef	3 oz	2 oz
• Onion	¼ cup	¼ cup
• Beef gravy, water-based	1 T	1 T
• Turnip greens	½ cup	½ cup
• Margarine, diet	½ tsp	½ tsp
• Sweet potato, baked	1 small	1 small
• Margarine, diet	½ tsp	¼ tsp
• Ground cinnamon	1 tsp	1 tsp
• Brown sugar	1 tsp	1 tsp
• Corn bread prepared with
margarine, diet	½ medium slice	½ medium slice
• Honeydew melon	¼ medium	⅛ medium
• Iced tea, sweetened with sugar	1 cup	1 cup
Snack
• Saltine crackers, unsalted tops	4 crackers	4 crackers
• Mozzarella cheese, part skim, low sodium	1 oz	1 oz
Calories … 1,653	Calories … 1,225
Total carbohydrate, % kcals … 53	Total carbohydrate, % kcals … 50
Total fat, % kcals … 28	Total fat, % kcals … 31
*Sodium, mg …1,231	*Sodium, mg … 867
Saturated fat, % kcals …8	Saturated fat, % kcals … 9
Cholesterol, mg … 172	Cholesterol, mg … 142
Protein, % kcals … 20	Protein, % kcals … 21
1,600: 100% RDA met for all nutrients except vitamin E 97%, magnesium 98%, iron 78%, and zinc 90%.
1,200: 100% RDA met for all nutrients except vitamin E 82%, vitamin B1 & B2 95%, vitamin B3 99%, vitamin B6 88%, magnesium 83%, iron 56%, and zinc 70%.
*No salt added in recipe preparation or as seasoning. Consume at least 32 ounces of water.
SOURCE: "Appendix D. Sample Reduced Calorie Menus: Southern Cuisine—Reduced Calorie," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

serious medical consequences, particularly for participants with cardiovascular disease, Type 2 diabetes mellitus, hyperlipidemia, or hypertension. Specifically, it has been cautioned that low-carbohydrate diets cause the accumulation of ketones, which may result in abnormal TABLE 5.7
Sample reduced calorie menus, Asian American cuisine—reduced calorie

	1,600 Calories	1,200 Calories
Breakfast
• Banana	1 small	1 small
• Whole wheat bread	2 slices	1 slice
• Margarine	1 tsp	1 tsp
• Orange juice	¾ cup	¾ cup
• Milk 1%, lowfat	¾ cup	¾ cup
Lunch
• Beef noodle soup, canned, low sodium	½ cup	½ cup
• Chinese noodle and beef salad:
Roast beef	3 oz	2 oz
Peanut oil	1½ tsp	1 tsp
Soy sauce, low sodium	1 tsp	1 tsp
Carrots	½ cup	½ cup
Zucchini	½ cup	½ cup
Onion	¼ cup	¼ cup
Chinese noodles, soft type	¼ cup	¼ cup
• Apple	1 medium	1 medium
• Tea, unsweetened	1 cup	1 cup
Dinner
• Pork stir-fry with vegetables:
Pork cutlet	2 oz	2 oz
Peanut oil	1 tsp	1 tsp
Soy sauce, low sodium	1 tsp	1 tsp
Broccoli	½ cup	½ cup
Carrots	1 cup	½ cup
Mushrooms ¼ cup ½ cup
• Steamed white rice 1 cup ½ cup
• Tea, unsweetened 1 cup 1 cup
Snack
• Almond cookies	2 cookies	—
• Milk 1%, lowfat	¾ cup	¾ cup
Calories … 1,609	Calories … 1,220
Total carbohydrate, % kcals … 56	Total carbohydrate, % kcals … 55
Total fat, % kcals … 27	Total fat, % kcals … 27
*Sodium, mg …1,296	*Sodium, mg …1,043
Saturated fat, % kcals …8	Saturated fat, % kcals …8
Cholesterol, mg … 148	Cholesterol, mg … 117
Protein, % kcals … 20	Protein, % kcals … 21
1,600: 100% RDA met for all nutrients except zinc 95%, iron 87%, and calcium 93%.
1,200: 100% RDA met for all nutrients except vitamin E 75%, calcium 84%, magnesium 98%, iron 66%, and zinc 77%.
*No salt added in recipe preparation or as seasoning. Consume at least 32 ounces of water.
SOURCE: "Appendix D. Sample Reduced Calorie Menus: Asian American Cuisine—Reduced Calorie," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

metabolism of insulin, impaired liver and kidney function, and salt and water depletion that may cause postural hypotension (sudden drop in blood pressure when rising from sitting) as well as fatigue, constipation, and kidney stones. It has also been posited that excessive consumption of animal proteins and fats may promote hyperlipidemia, and that higher dietary protein loads that may impair kidney function.

Not surprisingly, the investigators found that diets that restricted calorie intake and were longer in duration TABLE 5.8
Sample reduced calorie menus, Mexican American cuisine—reduced calorie

	1,600 Calories	1,200 Calories
Breakfast
• Cantaloupe	1 cup	½ cup
• Farina, prepared with 1% lowfat milk	½ cup	½ cup
• White bread	1 slice	1 slice
• Margarine	1 tsp	1 tsp
• Jelly	1 tsp	1 tsp
• Orange juice	1 ½ cup	¾ cup
• Milk, 1%, lowfat	½ cup	½ cup
Lunch
• Beef enchilada:
Tortilla, corn	2 tortillas	2 tortillas
Lean roast beef	2 ½ oz	2 oz
Vegetable oil	⅔ tsp	⅔ tsp
Onion	1 T	1 T
Tomato	4 T	4 T
Lettuce	½ cup	½ cup
Chili peppers	2 tsp	2 tsp
Refried beans, prepared with vegetable oil	¼ cup	¼ cup
• Carrots	5 sticks	5 sticks
• Celery	6 sticks	6 sticks
• Milk, 1%, lowfat	½ cup	—
• Water	—	1 cup
Dinner
• Chicken taco:
Tortilla, corn	1 tortilla	1 tortilla
Chicken breast, without skin	2 oz	1 oz
Vegetable oil	⅔ tsp	⅔ tsp
Cheddar cheese, lowfat and low sodium	1 oz	½ oz
Guacamole	2 T	1 T
Salsa	1 T	1 T
• Corn, seasoned with	½ cup	½ cup
Margarine	½ tsp	—
• Spanish rice without meat	½ cup	½ cup
• Banana	1 large	½ large
• Coffee	1 cup	½ cup
• Milk, 1%	1 oz	1 oz
Calories … 1,638	Calories … 1,239
Total carbohydrate, % kcals … 56	Total carbohydrate, % kcals … 58
Total fat, % kcals … 27	Total fat, % kcals … 26
*Sodium, mg …1,616	*Sodium, mg …1,364
Saturated fat, % kcals …9	Saturated fat, % kcals … 8
Cholesterol, mg … 143	Cholesterol, mg … 91
Protein, % kcals … 20	Protein, % kcals … 19
1,600: 100% RDA met for all nutrients except vitamin E 97% and zinc 84%.
1,200: 100% RDA met for all nutrients except vitamin E 71%, vitamin B1 & B3 91%, vitamin B2 & iron 90%, and calcium 92%.
* No salt added in recipe preparation or as seasoning. Consume at least 32 ounces of water.
SOURCE: "Appendix D. Sample Reduced Calorie Menus: Mexican American Cuisine—Reduced Calorie," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

were associated with weight loss. They also observed that when lower-carbohydrate diets resulted in weight loss, it was likely due to the restriction of calorie intake and longer duration rather than changes in carbohydrate intake. The investigators did, however, observe that at least in the short term, low-carbohydrate diets were not associated with the anticipated adverse effects on lipid levels, glucose levels, or blood pressure. Further, their TABLE 5.9
Sample reduced calorie menus, Lacto–ovo vegetarian cuisine—reduced calorie

	1,600 Calories	1,200 Calories
Breakfast
• Orange	1 medium	1 medium
• Pancakes, made with 1% lowfat milk and egg whites	3 4″circles	2 4″circles
• Pancake syrup	2 T	1 T
• Margarine, diet	1 ½ tsp	1 ½ tsp
• Milk, 1%, lowfat	1 cup	½ cup
• Coffee	1 cup	1 cup
• Milk, 1%, lowfat	1 oz	1 oz
Lunch
• Vegetable soup, canned, low sodium	1 cup	cup
• Bagel	1 medium	medium
• Processed American cheese, lowfat	¾ oz	—
• Spinach salad:
Spinach	1 cup	1 cup
Mushrooms	½ cup	½ cup
• Salad dressing, regular calorie	2 tsp	2 tsp
• Apple	1 medium	1 medium
• Iced tea, unsweetened	1 cup	1 cup
Dinner
• Omelette:
Egg whites	4 large eggs	4 large eggs
Green pepper	2 T	2 T
Onion	2 T	2 T
Mozzarella cheese, made from part	1 oz	½ oz
skim milk, low sodium	1 oz	½ oz
Vegetable oil	1 T	½ T
• Brown rice, seasoned with	½ cup	½ cup
Margarine, diet	½ tsp	½ tsp
• Carrots, seasoned with	½ cup	½ cup
Margarine, diet	½ tsp	½ tsp
• Whole wheat bread	1 slice	1 slice
• Margarine, diet	1 tsp	1 tsp
• Fig bar cookie	1 bar	1 bar
• Tea	1 cup	1 cup
• Honey	1 tsp	1 tsp
• Milk, 1%, lowfat	¾ cup	¾ cup
Calories … 1,653	Calories … 1,225
Total carbohydrate, % kcals … 53	Total carbohydrate, % kcals … 50
Total fat, % kcals … 28	Total fat, % kcals … 31
*Sodium, mg …1,231	*Sodium, mg … 867
Saturated fat, % kcals …8	Saturated fat, % kcals … 9
Cholesterol, mg … 172	Cholesterol, mg … 142
Protein, % kcals … 20	Protein, % kcals … 21
1,600: 100% RDA met for all nutrients except vitamin E 92%, vitamin B3 97%, vitamin B6 67%, iron 73%, and zinc 68%.
1,200: 100% RDA met for all nutrients except vitamin E 75%, vitamin B1 92%, vitamin B3 69%, vitamin B 6 59%, iron 54%, and zinc 46%.
*No salt added in recipe preparation or as seasoning. Consume at least 32 ounces of water.
SOURCE: "Appendix D. Sample Reduced Calorie Menus: Lacto–Ovo Vegetarian Cuisine—Reduced Calorie," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

findings suggested that persons without diabetes tolerated a lower-carbohydrate diet better than higher-carbohydrate alternatives and that this diet may be an effective means of achieving short-term weight loss without significant adverse effects on serum lipid levels, glycemic control, or blood pressure. They cautioned, however, that TABLE 5.10
Food exchange list
Within each group, these foods can be exchanged for each other. You can use this list to give yourself more choices.

Vegetables contain 25 calories and 5 grams of carbohydrate. One serving equals: • ½ cup Cooked vegetables (carrots, broccoli, zucchini, cabbage, etc.) • 1 cup Raw vegetables or salad greens • ½ cup Vegetable juice If you're hungry, eat more fresh or steamed vegetables.	Fruits contain 15 grams of carbohydrates and 60 calories. One serving equals: • 1 small Apple, banana, orange, nectarine • 1 medium Fresh peach • 1 Kiwi • ½ Grapefruit • ½ Mango • 1 cup Fresh berries (strawberries, raspberries, or blueberries) • 1 cup Fresh melon cubes • ⅛ Honeydew melon • 4 oz Unsweetened juice • 4 tsp Jelly or jam
Fat free and very low fat milk contains 90 calories and 12 grams of carbohydrate per serving. One serving equals: • 8 oz Milk, fat free or 1% fat • ¼ cup Yogurt, plain nonfat or lowfat • 1 cup Yogurt, artificially sweetened
Very lean protein choices have 35 calories and 1 gram of fat per serving. One serving equals: • 1 oz Turkey breast or chicken breast, skin removed • 1 oz Fish fillet (flounder, sole, scrod, cod, haddock, halibut) • 1 oz Canned tuna in water • 1 oz Shellfish (clams, lobster, scallop, shrimp) • ¾ cup Cottage cheese, nonfat or lowfat • 2 each Egg whites • ¼ cup Egg substitute • 1 oz Fat free cheese • ½ cup Beans-cooked (black beans, kidney, chickpeas, or lentils): count as 1 starch/bread and 1 very lean protein	Lean protein choices have 55 calories and 2 to 3 grams of fat per serving. One serving equals: • 1 oz Chicken-dark meat, skin removed • 1 oz Turkey-dark meat, skin removed • 1 oz Salmon, swordfish, herring, catfish, trout • 1 oz Lean beef (flank steak, London broil, tenderloin, roast beef)* • 1 oz Veal, roast, or lean chop* • 1 oz Lamb, roast, or lean chop* • 1 oz Pork, tenderloin, or fresh ham* • 1 oz Lowfat cheese (3 grams or less of fat per ounce) • 1 oz Lowfat luncheon meats (with 3 grams or less of fat per ounce) • ¼ cup 4.5% cottage cheese • 2 medium Sardines *Limit to 1 to 2 times per week.
Medium fat proteins have 75 calories and 5 grams of fat per serving. One serving equals: • 1 oz Beef (any prime cut), corned beef, ground beef** • 1 oz Pork chop • 1 each Whole egg (medium) ** • 1 oz Mozzarella cheese • ¼ cup Ricotta cheese • 4 oz Tofu (note that this is a heart-healthy choice) ** Choose these very infrequently.	Starches contain 15 grams of carbohydrate and 80 calories per serving. One serving equals: • 1 slice Bread (white, pumpernickel, whole wheat, rye) • 2 slice Reduced calorie or "lite" bread • ¼ (1 oz) Bagel (varies) • ½ English muffin • ½ Hamburger bun • ¾ cup Cold cereal • ⅓ cup Rice, brown or white-cooked • ⅓ cup Barley or couscous-cooked • ⅓ cup Legumes (dried beans, peas, or lentils)-cooked • ½ cup Pasta-cooked • ½ cup Bulgur-cooked • ½ cup Corn, sweet potato, or green peas • 3 oz Baked sweet or white potato • ¾ oz Pretzels • 3 cups Popcorn, hot-air popped or microwave (80-percent light)
Fats contain 45 calories and 5 grams of fat per serving. One serving equals: • 1 tsp Oil (vegetable, corn, canola, olive, etc.) • 1 tsp Butter • 1 tsp Stick margarine • 1 tsp Mayonnaise • 1 T Reduced fat margarine or mayonnaise • 1T Salad dressing • 1 T Cream cheese • 2 T Lite cream cheese • ⅛ Avocado • 8large Black olives • 10 large Stuffed green olives • 1 slice Bacon
SOURCE: "Appendix E. Food Exchange List," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

there is still inadequate evidence to recommend or condemn the use of low-carbohydrate diets among persons with diabetes or for long-term use.

Michael Dansinger and his colleagues at Tufts University, New England Medical Center, compared the effectiveness of four popular diets—Atkins (low carbohydrates), the Zone (moderate carbohydrates), Ornish (lowfat vegetarian), and Weight Watchers (moderate fat). They presented the results of their study, funded by a National Institutes of Health (NIH) grant, the Tufts-New England Medical Center, and the USDA Nutrition Research Center at Tufts, at the scientific sessions of the American Heart Association meeting in November 2003.

Study participants were asked to follow the diets they were given as best they could for two months, and they were given official diet cookbooks and assigned to small group classes for diet education. For the remaining ten months the participants were told to follow their assigned diets "to whatever extent they wanted." The investigators reported that nearly one-quarter of the participants (22 percent) had dropped out of each diet after just two months, and by twelve months half of the participants assigned to TABLE 5.11
Low calorie, lower fat alternatives

Instead of…		Replace with…
• Evaporated whole milk • Whole milk • Ice cream	Dairy products	• Evaporated fat free (skim) or reduced fat (2%) milk • Lowfat (1%), reduced fat (2%), or fat free (skim) milk • Sorbet, sherbet, lowfat or fat free frozen yogurt, or ice milk (check label for calorie content) • Imitation whipped cream (made with fat free [skim] milk) or lowfat vanilla yogurt • Plain lowfat yogurt • Neufchatel or "light" cream cheese or fat free cream cheese • Reduced calorie cheese, low calorie processed cheeses, etc. • Fat free cheese • Fat free American cheese or other types of fat free cheeses • Lowfat (1%) or reduced fat (2%) cottage cheese • Part skim milk, low-moisture mozzarella cheese • Part skim milk ricotta cheese • Lowfat (1%) or reduced fat (2%) milk or nonfat dry milk powder
• Whipping cream • Sour cream • Cream cheese • Cheese (cheddar, Swiss, jack)
• American cheese • Regular (4%) cottage cheese • Whole milk mozzarella cheese • Whole milk ricotta cheese • Coffee cream (half and half) or nondairy creamer (liquid, powder)
• Ramen noodles • Pasta with white sauce (alfredo) • Pasta with cheese sauce • Granola	Cereals, grains, and pasta	• Rice or noodles (spaghetti, macaroni, etc.) • Pasta with red sauce (marinara) • Pasta with vegetables (primavera) • Bran flakes, crispy rice, etc. • Cooked grits or oatmeal • Whole grains (e.g., couscous, barley, bulgur, etc.) • Reduced fat granola
• Cold cuts or lunch meats (bologna, salami, liverwurst, etc.) • Hot dogs (regular) • Bacon or sausage • Regular ground beef • Chicken or turkey with skin, duck, or goose • Oil-packed tuna • Beef (chuck, rib, brisket) • Pork (spareribs, untrimmed loin) • Frozen breaded fish or fried fish (homemade or commercial) • Whole eggs • Frozen TV dinners (containing more than 13 grams of fat per serving)	Meat, fish, and poultry	• Lowfat cold cuts (95% to 97% fat free lunch meats, lowfat pressed meats) • Lower fat hot dogs • Canadian bacon or lean ham • Extra lean ground beef such as ground round or ground turkey (read labels) • Chicken or turkey without skin (white meat) • Water-packed tuna (rinse to reduce sodium content) • Beef (round, loin) (trimmed of external fat) (choose select grades) • Pork tenderloin or trimmed, lean smoked ham • Fish or shellfish, unbreaded (fresh, frozen, canned in water) • Egg whites or egg substitutes • Frozen TV dinners (containing less than 13 grams of fat per serving and lower in sodium) • Turkey sausage, drained well (read label) • Vegetarian sausage (made with tofu)
• Chorizo sausage
• Croissants, brioches, etc. • Donuts, sweet rolls, muffins, scones, or pastries • Party crackers • Saltine or soda crackers (choose lower in sodium) • Cake (pound, chocolate, yellow) • Cookies	Baked goods	• Hard French rolls or soft "brown'n serve" rolls • English muffins, bagels, reduced fat or fat free muffins or scones • Lowfat crackers (choose lower in sodium)
		• Cake (angel food, white, gingerbread) • Reduced fat or fat free cookies (graham crackers, ginger snaps, fig bars) (compare calorie level)
• Nuts • Ice cream, e.g., cones or bars • Custards or puddings (made with whole milk)	Snacks and sweets	• Popcorn (air-popped or light microwave), fruits, vegetables • Frozen yogurt, frozen fruit, or chocolate pudding bars • Puddings (made with skim milk)
• Regular margarine or butter • Regular mayonnaise • Regular salad dressings	Fats, oils, and salad dressings	• Light-spread margarines, diet margarine, or whipped butter, tub or squeeze bottle • Light or diet mayonnaise or mustard • Reduced calorie or fat free salad dressings, lemon juice, or plain, herb-flavored, or wine vinegar • Jelly, jam, or honey on bread or toast • Nonstick cooking spray for stir-frying or sautéing • As a substitute for oil or butter, use applesauce or prune puree in baked goods
• Butter or margarine on toast or bread • Oils, shortening, or lard
• Canned cream soups • Canned beans and franks • Gravy (homemade with fat and/or milk)	Miscellaneous	• Canned broth-based soups • Canned baked beans in tomato sauce • Gravy mixes made with water or homemade with the fat skimmed off and fat free milk included • Chocolate syrup • Cucumber slices or lettuce leaves • Salsa
• Fudge sauce • Avocado on sandwiches • Guacamole dip or refried beans with lard
SOURCE: "Appendix C. Low Calorie, Lower Fat Alternatives," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

low-carbohydrate or low-fat vegetarian diets had dropped out, as had 35 percent of participants assigned to the moderate carbohydrates and moderate fat diets. For those participants who adhered, weight loss and reduction in cardiac risk scores as measured by reductions in low-density lipoprotein (LDL cholesterol) and insulin levels were comparable TABLE 5.12
Fat free or reduced fat versus regular

Fat free or reduced fat		Regular
	Calories		Calories
Reduced fat peanut butter, 2 T	187	Regular peanut butter, 2 T	191
Cookies:		Cookies:
Reduced fat chocolate chip cookies, 3 cookies (30 g)	118	Regular chocolate chip cookies, 3 cookies (30 g)	142
Fat free fig cookies, 2 cookies (30 g)	102	Regular fig cookies, 2 cookies (30 g)	111
Ice cream:		Ice cream:
Nonfat vanilla frozen yogurt (1% fat), ½ cup	100	Regular whole milk vanilla frozen yogurt (3–4% fat), ½ cup	104
Light vanilla ice cream (7% fat), ½ cup	111	Regular vanilla ice cream (11% fat), ½ cup	133
Fat free caramel topping, 2 T	103	Caramel topping, homemade with butter, 2 T	103
Lowfat granola cereal, approx. ½ cup (55 g)	213	Regular granola cereal, approx ½ cup (55 g)	257
Lowfat blueberry muffin, 1 small (2 ½ inch)	131	Regular blueberry muffin, 1 small (2 ½ inch)	138
Baked tortilla chips, 1 oz.	113	Regular tortilla chips, 1 oz.	143
Lowfat cereal bar, 1 bar (1.3 oz.)	130	Regular cereal bar, 1 bar (1.3 oz.)	140
SOURCE: "Fat Free or Reduced Fat versus Regular," in The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, National Institutes of Health, National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity, Silver Spring, MD, June 1998 [Online] http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf [accessed December 30, 2003]

for participants on the low-carbohydrate, moderate-carbohydrate, and moderate-fat plans. According to the study, the Ornish diet (low-fat vegetarian) "was best for lowering 'bad' LDL cholesterol, while other diets were better at raising 'good' HDL cholesterol."

The investigators concluded that their research "demonstrated that all these diets work." They also reiterated the importance of tailoring the selection of a weight-loss diet to ensure adherence, asserting "That means that physicians can work with patients to select the diet that is best suited to the patient. For example, if you have a patient who likes meat, it is unlikely that he or she will comply with the Ornish diet" (American Heart Association Scientific Sessions, Abstract 3535, November 12, 2003).

In "Low-Carb, Low-Fat Diet Gurus Face Off" (Journal of the American Medical Association, vol. 289, no. 14, April 2003), author Joan Stephenson asked the champions of the opposing regimens to offer their opinions about weight-loss approaches and the obesity epidemic. Dr. Atkins observed that low-carbohydrate dieters experienced more weight loss and greater improvements in LDL cholesterol and HDL than persons on low-fat diets. He explained that while persons on his plan consume about 40 percent of their calories from fat, as opposed to the U.S. average of 30 percent, the increased fat consumption is not harmful because "When the carbohydrate content is low, the fat takes a different metabolic pathway and forms energy through ketones, which then gets burned up right away. So the ketones do not accumulate because they're being used for energy."

In the same article, Dr. Ornish asserted that the overall health benefits of a low-fat diet were greater because carbohydrates are less calorie dense than protein and fat and that this diet sharply limits consumption of disease-promoting substances such as saturated fat and dietary cholesterol while increasing intake of protective nutrients such as phytochemicals, carotenoids, and lycopene—substances found in fruits, vegetables, grains, beans, and soy products. Ornish also observed that while there is not yet any data indicating that low-carbohydrate diets can reverse coronary heart disease, low-fat diets have been found to not only produce weight loss but also to reverse heart disease as measured by quantitative arteriography (systematic examination of the arteries using an injected contrast material that can be seen using x-ray equipment) and other cardiac imaging studies.

So while there is no single winner in the diet wars, recent research has dispelled some fears about the safety and effectiveness of the low-carbohydrate diet. Low-carbohydrate diets appear to be safe and effective in the short term, but long-term outcomes still are unclear. Although some results suggest that higher protein and fat intakes lead to lower total caloric intake by producing earlier satiety, these diets have not been shown to alter fundamental eating behaviors nor have they demonstrated, as many of their proponents argue, the ability to modify caloric balance such that weight loss persists when more calories are consumed than expended.