Why Restricting Calories May Not Be Healthy

The Truth behind Very Low Calorie Diets (VLCDs)

Very Low Calorie Diets (VLCDs) Come with Health Risks. Photodisc/Getty Images

In our fast paced society, the Very Low-Calorie Diet (VLCD) is quickly becoming the chosen fad or method of weight loss. It even comes with a guarantee of shedding those unwanted pounds yesterday.

Extreme measures of weight loss may be warranted and prescribed during a medical crisis. This would be understandable. However, applying drastic weight loss methods for the everyday person may not be safe or healthy.

Many very low-calorie diets (VLCDs) are now being covered by insurance plans. This has made it even more appealing for people to sign on the dotted line. Not usually understood is only part of the VLCD program may be covered by insurance. The diet shakes are the largest part of the VLCD and a costly pay-out-of-pocket product. 

Be cautious about any diet making unrealistic weight loss claims. Extreme weight loss programs may severely restrict food intake and recommend drinking shakes in lieu of eating. Studies on very low-calorie diets (VLCDs) do show rapid weight loss but not without adverse health risks. According to other research, once the VLCD plan is completed, the weight is gained back plus more. 

The human body requires nutrients from lean proteins, carbohydrates, and healthy fats . Proper portions of these macronutrients are essential for good health. Individual calorie requirements will differ per person based on overall lifestyle and activity levels.


A sedentary person would require much less in caloric intake compared to a marathon runner for example. Regardless of lifestyle, the human body needs calories from the major food groups to function at optimum levels and to be healthy. Very low-calorie diets (VLCDs) can restrict essential nutrients and place a person at risk for adverse effects and health issues.


Energy needs for a body at rest (Basal Metabolic Rate) remain fairly consistent and responsible for seventy percent of calories burned each day. To calculate your basal metabolic rate, multiply ten calories for each pound of bodyweight for a woman and eleven calories for a man. 

A 130lb woman would burn 1300 calories at rest per day. More energy is required for digestion and absorption (thermogenesis) ranging from one to eight hundred additional calories per day. Physical activity calories also offer the largest variable per person demanding even more caloric intake.  

According to the American College of Sports Medicine, a woman should consume no less than 1200 calories per day and a man no less than 1800 calories. Also indicated extreme caloric restrictions signals the body to conserve calories and significantly reduces our metabolic rate. Very low-calorie diets (VLCDs) allow for consumption of only 500-800 calories per day and places the body into self-starvation. 

Very low-calorie diets (VLCDs) require a person to be under the care of a physician due to possible health risks. Some adverse effects may include fatigue, dizziness, constipation, nausea, diarrhea, and increased overall cholesterol.

Research has indicated more serious health effects may include gall stone development.

Very low-calorie diets(VLCDs) promise rapid weight loss but not a lifestyle of keeping it off. Studies show weight loss with VLCDs is commonly regained once the program is completed. Participants are not learning how to eat healthily or exercise consistently. 

The safest way to lose weight is implementing healthy methods. Nutrition and fitness education is important. Learn how to buy and prepare healthy foods and include a regular exercise program. It will be proper nutrition and exercise knowledge allowing life long sustainable weight loss.

Instead of overspending on packaged shakes for a temporary fix, a better investment plan would be to locate a qualified personal trainer and/or certified nutritionist. They will be able to offer substantially more quality education for a life time of good health.   


 A Quarterly Publication of the American College of Sports Medicine, acsm.org, Summer 2010, pg. 5

Metabolism is Modifiable with the Right Lifestyle Changes, American College of Sports Medicine, In the News, acsm.org, 8/1/2011

Very Low-Calorie Diets, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (www.niddk.nih.gov), 10/11/2004










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