16.8 pounds of weight gain to be exact.

A study by the Harvard School of Public Health and Brigham Women’s Hospital found that bad habits in lifestyle factors, food choices, physical activity and sleep habits all add up to an average of 16.8 pound weight gain over a 20 year period.

Food choices had the greatest impact on weight creep. The foods that contributed most to weight gain when consumed daily were: potato chips, french fries, margarine, breaded or coated chicken or fish, sugar-sweetened beverages (like soda, coffee-drinks and energy drinks), milk, refined grains (like white bread) and processed meats. Eliminating these foods could help prevent slow weight gain.

There were people in the study who lost or maintained weight. Guess what – those people reported eating minimally processed foods. Increased intake of fruits, vegetables, whole grain and nuts resulted in weight loss. Researchers presumed this was because they were replacing “bad” foods in the diet.

What does this all mean?

What this is really saying is that not all foods are good or even “OK” for you, even in moderation.

Different foods cause different reactions in the body, not every calorie is the same. Some foods are bad for you, even if you only have them sometimes or for a treat.

Mozaffarian D, Hao T, Rimm EB, et al. Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men. N Engl J Med 2011; 364:2392-2404. June 23, 2011.