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Health Risks of Very Low-Calorie Diets

The Health Risks of Very Low-Calorie Diets A very low calorie diet (VLCD), which consists of less than 800 kcal/day, is a rapid approach to weight loss that, without proper guidelines, could be detrimental to and have adverse effects on health. Any time you restrict or lower calories, you run the risk of losing muscle mass for daily living, performance and energy due to the negative effects of chronic glycogen depletion and hydration levels.(1) This typically leads to a decrease in physical performance and cognitive function. There is an increased risk of both malnutrition and nutrient deficiencies which can also significantly influence day-to-day energy, performance, behavior and emotional state.(2)

The Health Risks of Eating Disorders Dissatisfaction with body weight and image is a common problem among the general population and specifically teenagers.(3) This dissatisfaction can lead to inaccurate perceptions of body weight and image therefore, leading to detrimental behaviors such as anorexia nervosa, bulimia and body image distortion (body dysmorphic disorder). There is a strong correlation between eating disorders, stress, anxiety and depression among the general population, college students and athletes under pressure to maintain an ideal body weight for performance, qualifications and social norms. Physical symptoms can include a slowed heart rate and reduction in blood pressure, reduction in bone density, muscle loss and weakness, hormone imbalance, dehydration (which could also lead to kidney failure), dry hair, hair loss and hair growth in new, unexpected areas (which may be a result of hormone imbalance). In addition, a common side effect is electrolyte imbalances due to the fluctuation in sodium, potassium and chloride levels in the body. Inflammation, tooth decay, constipation and along with an increased risk for ulcers, diabetes, and variation in cholesterol levels can significantly be impacted with eating disorders.(4)

The Female Triad The health risks mentioned above apply to the general population with respect to VLCDs and eating disorders. When it comes to women, however, and in particular female athletes, there are additional considerations. As an example, we turn to – a 17 year-old female gymnast. As she is constantly interjected into a team setting, she witnesses fellow athletes skip meals, guided by the pressures of the coach. The pressure to comply forces her to follow the same prescription. After skipping meals and purging, she is noticing a decrease in physical stamina. If she skips enough meals, she will be lacking in nutrients, leading to a cascade of events, and possibly the “female triad”. The female triad can be explained as the interplay between three conditions. Stated differently, the onset of one condition can significantly influence the onset of another condition. The three conditions include disordered eating, amenorrhea (absence of the menses, which signifies a hormonal imbalance halting ovulation), and osteoporosis (loss of bone density). It is important for parents, coaches, athletes, and other third parties (dieticians, physicians) to closely monitor this behavior to ensure that this condition does not continue to worsen or lead to new and potentially more serious symptoms, including heart failure and death.(1)

Impact of Dieting on Performance An improper, imbalanced diet can negatively impact performance. Both a lack of nutrients and dehydration will result in a reduction in body mass which is usually accompanied by a reduction muscle mass and a reduction in muscle glycogen. A lower amount of muscle mass and the inability to use muscle glycogen for energy will undoubtedly lead to a performance decline. In addition, another common side effect of dietary issues is chronic fatigue, which may be a factor in an increased injury risk (in addition to a loss in bone density). With the above risks of dieting, it is important for our athlete/gymnast and coach to discuss the pros and cons of any prescribed nutrition plan. Without a sense of the potential benefits of any nutrition or diet plan, it possible that a particular prescribed diet is counterintuitive to the training objective and overall health, which is what we are seeing with our gymnast example above.(1) Rationale of Recommendations A planned and strategic reduction in calories is generally advised for most people. A dietician or other skilled professional should be involved in prescribing an appropriate diet for the female gymnast, incorporating recommendations on fat, protein and carbohydrates, with the overall objective in mind (goal weight, body fat percentage). Depending on the athlete’s state of mind, physical and emotional well-being, the dietician should also make recommendations to ensure that she is getting the minimum recommended daily allowance of the requisite vitamins and minerals. Under most circumstances, there is no rationale for skipping meals or purging. A skilled professional should strongly advise against skipping meals and perhaps refer both the athlete and coach to a counselor to see if there are any psychological implications due to the current diet plan. Further, the coach should be reported to the appropriate licensing or review board for encouraging behaviors that are deleterious to the health of the team. The athlete should become accustomed to keeping a 7-day food diary to investigate food choices and determine healthy alternatives for maintaining both a caloric and nutrient balance.

Dan Tatro, M.S.-CSCS, CEO Patriot Fitness Academy

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1. Jeukendrup, A., & Gleeson, M. (2010). Sport nutrition: An introduction to energy production and performance (2nd ed.). Champaign, IL: Human Kinetics. ISBN: 9780736079624.

2. Damms-Machado, Antje et al. Micronutrient Deficiency in Obese Subjects Undergoing Low Calorie Diet. Nutrition Journal. 2012;11(34). doi:10.1186/1475-2891-11-34.

3. Tavolacci, Marie Pierre, et al. Eating Disorders and Associated Health Risks Among

University Students. Journal of Nutrition Education and Behavior. 2015;47(5), 412-420. doi:10.1016/j.jneb.2015.06.009.

4. Health Consequences of Eating Disorders. National Eating Disorders Association. 2012. Accessed January 10, 2021.

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