The Science of Weight Gain

by Troy Purdom and Len Kravitz, PhD on Jul 14, 2015

Fitness professionals expend considerable energy helping people to lose weight, but there’s another way to view this challenge: What are the main factors that cause people to gain weight?

Research shows that two-thirds of Americans are overweight or obese (Ogden et al. 2014), a health condition associated with hypertension, cardiovascular disease, diabetes, depression and various cancers (breast, endometrial, colon and prostate) (Malik, Schultz & Hu 2006). Furthermore, studies find that Americans tend to gain weight slowly over time after age 50—adding approximately 1 pound per year (Mozaffarian et al. 2011). 

Understanding the specific behaviors that increase the risk of weight gain is essential to helping clients manage their weight. While most weight management articles focus on strategies and behaviors for losing weight, we will examine the other side of the coin: six factors that predict weight gain over the American lifespan. 

  1. Eating High-Calorie Foods
  2. Consuming Sugar-Sweetened Beverages
  3. Sleeping Too Little (or Too Much)
  4. Watching a Lot of TV
  5. Overconsuming Alcohol
  6. Not Engaging in Enough Physical Activity

To read a more in-depth discussion about these 6 factors behind weight gain, please see "6 Key Factors That Predict Weight Gain" in the online IDEA Library or in the May 2015 print issue of IDEA Fitness Journal. If you cannot access the full article and would like to, please contact the IDEA Inspired Service Team at (800) 999-4332, ext. 7.

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Malik, V.S., Schulze, M.B., & Hu, F.B. 2006. Intake of sugar-sweetened beverages and weight gain: A systematic review. American Journal of Clinical Nutrition, 84 (2), 274-88.

Mozaffarian, D., et al. 2011. Changes in diet and lifestyle and long-term weight gain in women and men. The New England Journal of Medicine, 364 (25), 2392-2404.

Ogden, C.L., et al. 2014. Prevalence of childhood and adult obesity in the United States, 2011-2012. Journal of the American Medical Association, 311 (8), 806-14.

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About the Authors

Troy Purdom

Troy Purdom IDEA Author/Presenter

Len Kravitz, PhD

Len Kravitz, PhD IDEA Author/Presenter

Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico in Albuquerque, where he recently won the Outstanding Teacher of the Year award. Len was also honored as the 2006 Fitness Educator of the Year by the American Council on Exercise.