Short-term, very low-calorie diets for obese teenagers are safe as long as they are closely monitored by an experienced dietitian, according to researchers in Australia.
The study, by scientists based at the University of Sydney, also revealed that many adolescents involved in the investigation thought the diets were an acceptable way to lose weight – despite their side effects experienced which include fatigue, headache, irritability, constipation and nausea.
Very low energy diets (VLED) involve eating less than 800 calories per day and are prescribed for obese people who want to lose weight but who do not respond to conventional diets and exercise programs.
However, concerns have been raised about the risks associated with making such rapid reductions in body mass while ensuring that young people are given all essential nutrients. There is limited data on the impact of VLEDs on the growth, heart health and psychological well-being of the subjects.
However, the Sydney study indicated that such fears are unwarranted. “Given the associated rapid weight loss, its use should be emphasized in clinical practice guidelines for the treatment of severe obesity and obesity-related complications in adolescents, especially before pharmacological or surgical intervention,” says Dr Megan Gow, who led the study.
A total of 71 men and 70 women with obesity and at least one related condition, such as high blood pressure or insulin resistance, participated. They were put on four-week diets that included formulated meal replacements and low-carb vegetables, such as broccoli and tomatoes.
Of the 141 who started the study, 134 completed it and lost an average of 5.5 kg in weight. Almost all (95%) had at least one side effect, with 70% experiencing three. Hunger, fatigue and headaches were the most common.
Losing weight was the most popular aspect, participants reported, while restrictive dieting and taste of meal replacements were least liked.
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The researchers conclude that a health professional-monitored VLED can be implemented safely in the short term and, despite side effects, is acceptable for many adolescents with moderate to severe obesity.
