Carbohydrates And Body Weight

In the 80’s and 90’s, dietary fat was the major focus of most weight loss strategies. Starting in the early 2000’s, the research literature started to show that carbohydrates were also important in weight maintenance. Most current fad diets manipulate the amount or type of carbohydrate permitted in some way. 

Harvard University’s Department of Nutrition recently published an impressive study examining the weight loss impact of different type of carbohydrate foods over a 24 year follow-up.

The Study

In this investigation, 136,432 men and women from Harvard’s Nurses’ Health Study, Nurses’ Health Study 2 and Health Professional Follow-up study had their 4 year weight change and diet measured for 24 years (Reference 1). 

The results were very interesting: (As a reference, 100 grams is just less than ½ of a cup)

-An increase in glycemic index and glycemic load were positively associated with weight gain.

-A 100 gram per day increase in added sugar resulted in a 4 year weight gain of 2 lbs.

-A 100 gram per day increase in refined grains resulted in a 4 year weight gain of 1.8 lbs.

-A 100 gram per day increase in potatoes and other starchy vegetables resulted in a 4 year weight gain of 5.7 lbs.

-A 100 gram per day increase in whole grains resulted in a 4 year weight loss of .9 lbs.

-A 100 gram per day increase in fruit resulted in a 4 year weight loss of 3.5 lbs.

-A 100 gram per day increase in non-starchy vegetable resulted in a 4 year weight loss of 6.6 lbs.

Conclusions And Recommendations

If you are trying to control your weight, you need to pay close attention to the type of carbs on your plate. However, there is no need to completely eliminate them. Carbohydrate foods are our best sources of fiber, vitamins, minerals and cancer fighting phytochemicals.

Focus on fruits, vegetables, legumes (beans and lentils) and whole grains (brown rice, quinoa and oatmeal).

Limit sugar, potatoes and refined grains like white rice, bread and pasta.

References

1) Wan Y, et al. Association between changes in carbohydrate intake and long-term weight changes: Prospective cohort study. British Medical Journal 2023; 382:e073939.