Carbohydrate quality and long term weight gain

The Study
The glycemic load is a measure of how quickly and how severely the carbohydrate containing foods in your diet elevate your blood sugar. An interesting study was recently published that measured the impact of glycemic load on long term weight gain. Over 120,700 men and women from the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professional Follow-up Study were followed for 16-24 years. Changes in glycemic load and body weight were measured every 4 years throughout follow-up. 

There were 2 relevant findings: 1) Dietary glycemic load was independently associated with weight gain. Every four years, body weight increased .93 pounds for every 50 unit increase in glycemic load. 2) The glycemic load had a strong interaction with other foods. If a food was associated with weight gain, like red meat was in these cohorts, eating that food with high glycemic load carbs increased weight gain, while eating that food with low GL carbs decreased weight gain. The same was true for foods that were associated with reducing body weight, like plain yogurt. If high GL foods were consumed with the yogurt, the weight loss was attenuated.  If low GL foods were consumed with the yogurt, the weight loss was augmented. The American Journal of Clinical Nutrition 2015; 101:1216-24

Take Home Message

If weight loss is your goal, it is a good idea to pay attention to the glycemic load of your diet. Mechanisms by which a lower glycemic load diet promotes weight loss were discussed by the authors of this study. A higher resting energy expenditure, increased satiety, and reduced cravings with a low GL diet are all possibilities. If you want to lower the glycemic load of your diet, substitute fruits, vegetables, legumes and whole grains for bread, pasta, white rice and sugar. It is also a good idea to keep carbohydrates in the range of 45-50% of calories.