Why We Gain Weight

May 06, 2016

Fitness Handout

Are you or is someone you know struggling to lose weight? While most weight management articles focus on strategies and behaviors for losing weight, we will examine the other side of the coin: six behaviors that predict weight gain.

Understanding these behaviors can help you avoid them. Here are insights from Troy Purdom, MS, an exercise science doctoral student at the University of New Mexico, and Len Kravitz, PhD, program coordinator of exercise science and a researcher at UNM.


Mozaffarian et al. (2011) found that eating behaviors associated with progressive weight gain over multiple 4-year periods included regular consumption of

  • potato chips and potatoes (french fries; mashed, baked and boiled potatoes);
  • red meat, processed meats (like bacon and luncheon meats) and unprocessed red meats (like beef and pork);
  • butter, sweets and desserts; and
  • refined grains (foods like white flour and white rice).


In 2006, Malik, Schultz & Hu concluded that sugar-sweetened beverages accounted for approximately 8%–9% of total energy intake in children and adults. These drinks contain high-fructose corn syrup, sucrose and artificial sweeteners. Plus, you can drink a lot and still be hungry.


Some studies suggest that weight gain is influenced by sleeping less than 7 hours or more than 8 hours per night (Marshall, Glozier & Grunstein 2008). According to Marshall and colleagues, people who sleep too little develop chronically impaired glucose metabolism, steadily contributing to obesity.


Length of time spent watching television is highly associated with weight gain, especially in young people (Chapman et al. 2012). Chapman and associates tell us that 58.9% of Americans watch television for more than 2 hours per day. According to these authors, studies reveal that those who regularly watch more daily TV tend to
  • snack more while watching;
  • have higher overall calorie intake from foods; and
  • consume more energy-dense foods.
  • All these choices lead to weight gain.


Alcohol is very energy-dense—at 7 kilocalories per gram, it is second only to fat, with 9 kcal per gram. Plus, the additional kilocalories from alcohol do not seem to replace energy consumption from other sources (Yeomans 2010). Therefore, energy consumption from alcohol adds to overall daily calorie intake.


In studying 15-year trends, scientists have noted an inverse relationship between walking and weight gain (Gorden-Larsen et al. 2009), suggesting that the more people walk, the less likely they are to gain weight. The researchers suggest that adding 2–4 hours of walking per week is an attainable movement target.


Chapman, C.D., et al. 2012. Lifestyle determinants of the drive to eat: A meta-analysis. American Journal of Clinical Nutrition, 96 (3), 492–97.

Gordon-Larsen, P., et al. 2009. Fifteen-year longitudinal trends in walking patterns and their impact on weight change. American Journal of Clinical Nutrition, 89 (1), 19–26.

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.

Marshall, N.S., Glozier, N., & Grunstein, R.R. 2008. Is sleep duration related to obesity? A critical review of the epidemiological evidence. Sleep Medicine Reviews, 12 (4), 289–98.

Moza_ arian, 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.

Yeomans, M.R. 2010. Alcohol, appetite and energy balance: Is alcohol intake a risk factor for obesity? Physiology & Behavior, 100, 82–89.

Fitness Journal, Volume 13, Issue 6

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