Rates of overweight and obesity are alarmingly high. The U.S. Department of Agriculture reports that 64 percent of women and 72 percent of men in the United States are overweight or obese. Effective weight loss typically requires a daily calorie deficit. However, eating too few calories may cause certain health problems or side effects. Diets very low in calories should be used for weight loss only in certain circumstances.
Basics
Very reduced-calorie, or very low-calorie diets, also called VLCDs, are diets sometimes used for obese individuals. VLCDs are commonly less than 800 calories per day, often consist of commercially prepared shakes, formulas or bars and can lead to a substantial weight loss. However, due to the potential nutrition risks associated with consuming very low calorie diets, they should only be used under the supervision of a qualified medical professional.
When Appropriate
Doctor-supervised VLCDs may be recommended for obese individuals with a body mass index, or BMI, of greater than 30 and disease risk factors or people with BMIs of 27 to 30 and medical conditions such as high blood pressure. VLCDs may also be used for bariatric patients before and after their weight loss surgery.
Benefits
A rapid weight loss of 3 to 5 pounds per week is sometimes accomplished with a VLCD, which can improve certain health conditions such as high blood pressure, high cholesterol and diabetes.
Concerns
Very low-calorie diets may cause certain side effects such as fatigue and nausea and can lead to nutrient deficiencies if not followed properly. Gallstones are a common side effect when following a VLCD. Due to a rapid loss of weight, weight regain is also a concern when following a VLCD. According to the National Institutes of Health, very low-calorie diets of less than 800 calories per day are no more effective than low-calorie diets for weight loss.
Recommendations
For a weight loss of about 1 to 2 Ib. per week, the American Dietetic Association encourages a calorie deficit of 500 to 1,000 calories per day. This rate of weight loss is also recommended by the National Institutes of Health, who encourage low-calorie diets for weight loss of 1,000 to 1,200 calories per day for most overweight women and 1,200 to 1,600 calories per day for overweight men, active overweight women and women who weigh 165 Ibs. or more.
References
- U.S. Department of Agriculture: Dietary Guidelines for Americans 2010
- Weight-control Information Network: Very Low-calorie Diets
- National Institutes of Health: Identification, Evaluation and Treatment of Overweight and Obesity in Adults
- American Dietetic Association: Adult Weight Management (AWM) Realistic Weight Goal Setting
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