Comparing Weight Loss Diets

Popular Diets Don't Pass USDA Standards

Most popular diets are nutritionally inadequate, according to a report released from the USDA.  Comparing low-fat, moderate-fat, and high-fat / low-carb diets - researchers examined long-term results and nutritional quality of diet plans that focus on nutrient distributions of carbohydrate, protein and fat.

All diets analyzed resulted in weight loss.  Regardless of macronutrient composition, total calories consumed are decreased when a dieter follows a plan that restricts fat or carbohydrates.  Very low fat diets, like the one developed by Dr. Dean Ornish, are naturally higher in fiber and micronutrients due to the increased volume of fruits and vegetables.  Low-carbohydrate diets, like the one developed by Dr. Robert Atkins, also succeed also in weight loss because intake of fat and protein are self-limiting.

Popular diets fail, according to the report, when examining nutritional quality.  High-fat, low-carbohydrate diets are low in vitamins E, A, thiamin, B6, folate, calcium, magnesium, iron, zinc, potassium, and dietary fiber, and require dietary supplementation.  They are also often high in saturated fat and cholesterol.  On the opposite end, very-low-fat diets are deficient in vitamin B12 because meat intake is low. 

Type of Diet Fat   % Calories Carbohydrate  % Calories Protein % Calories 
 Low-fat and 
Very Low-fat		  <10-19 %  >65 %  10-20 %
 Moderate-fat  20-30 %  55-60 %  15-20 %
 Low-carbohydrate  55-65 %  <20 %  25-30 %
Examples of diets fitting the macronutrient compositions analyzed by the report include: Dr. Atkins New Diet Revolution, Protein Power, and Life Without Bread (high-fat, low-carbohydrate, high protein); Dr. Dean Ornish's Program for Reversing Heart Disease, Eat More - Weigh Less, The New Pritikin Program (low-fat, and very-low-fat, very-high-carbohydrate, moderate-protein diets); and the USDA Food Guide Pyramid, DASH diet, Weight Watchers (moderate-fat reduction diets, high in carbohydrate and moderate in protein).

The prevalence of overweight and obesity has increased steadily over the past 30 years, according to the report.  So much so, that 50% of all adult Americans are now considered overweight or obese.  Being overweight may increase risks of chronic conditions such as cardiovascular disease, type 2 diabetes, hypertension, stroke, gallbladder disease, osteoarthritis, and some types of cancer.