The following obesity facts presented by Casazza et al. are well supported by scientific evidence and offer practical guidance for personal trainers.

  • Meal-replacement products promote greater weight loss. It appears the structure and calorie intake regimen these products provide enhance weight-loss interventions.
  • Heredity is not destiny. While genetic factors play a role in weight gain, consistent changes in diet and exercise remain central to reducing body weight and preventing obesity.
  • Regardless of body weight, improving fitness has encouraging health benefits. Consistent exercise can reduce many of the damaging health effects of obesity.
  • Encouraging clients to go on a diet does not work well in the long term. Diets effectively reduce weight, but their lasting effects are limited (Donnelly et al. 2009). An overall sustainable lifestyle change that cuts calories and increases physical activity will produce supportable weight-loss goals and prevent weight regain much better than a diet.
  • Exercise in sufficient doses is a critical component of a successful weight-loss program. People need substantial exercise to lose weight and avoid gaining it back. ACSM recommends accumulating 250–300 minutes per week (~2,000 kilocalories per week) of moderate-intensity exercise for weight loss and prevention of weight gain (Donnelly et al. 2009).
  • Continuing the conditions that promote weight loss also promotes weight maintenance. Weight-regain prevention is an ongoing challenge that requires sustainable efforts of energy output and portion control.
  • With overweight children, programs that involve parental support at home have the best results. This does not devalue school, agency and organization efforts to promote weight loss in youth; it merely shows the importance of the home setting for sustain- able weight loss in this population.
  • A few pharmaceutical agents can help over- weight clients lose weight. Moderately effective medical treatments can be prescribed and administered by clinical professionals.
  • For severely obese people, bariatric surgery leads to successful weight loss and a reduction in the incidence of diabetes and mortality.

To view the full article which ran in the January 2014 issue of the IDEA Fitness Journal click here.


Casazza, K., et al. 2013. Myths, presumptions, and facts about obesity. The New England Journal of Medicine, 368 (5), 446-54.

Len Kravitz, PhD

Len Kravitz, PhD is a professor and program coordinator of exercise science at the University of New Mexico where he recently received the Presidential Award of Distinction and the Outstanding Teacher of the Year award. In addition to being a 2016 inductee into the National Fitness Hall of Fame, Dr. Kravitz was awarded the Fitness Educator of the Year by the American Council on Exercise. Just recently, ACSM honored him with writing the 'Paper of the Year' for the ACSM Health and Fitness Journal.

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