Training on an empty stomach for weight loss

(12-14-2014) To succesfully lose weightRunning the combination of a healthy diet with caloric restriction combined with training is more effective than using a diet or training alone. The last few years quite some research has been performed on endurance training on an empty stomach. These studies showed that fat metabolism was increased directly after fasted exercise compared with regular fed exercise. In addition fasted exercise improved insulin sensitivity and lead to a better glucose tolerance. These adaptations should in theory help weight and fat loss. To test this hypothesis, scientists performed a study to answer whether training on an empty stomach is more effective for weight loss.

 What did the reseachers do?

Twenty young women who were on average 22,4 years old were admitted to the study. All participants reported performing regular endurance training before starting in this study. Before and after the training period body weight, Body Mass Index (BMI)body composition using a BodPod and waist circumference were taken. The participants were put on a diet aimed at a daily energy deficit of 500 kcal. In addition the participants performed endurance exercise at three non consecutive days each week for a total of four weeks. The training consisted of running at a speed that corresponded with 70% of maximum heart rate (MHF) during 50 minutes with a 5 minute warming up and cooling down period at 50% MHF. The training was performed on a Life-Fitness treadmill. The participants were randomly divided in two groups. One group received a shake before the workout. One group performed the training on an empty stomach and received the same shake after the workout.

What were the results?

The results of the study are depicted in the figures below.

Fasted training effects on body weight












Figure 1: Effects on body weight in kg.


Fasted training effects on BMI












Figure 2: Effects on BMI.


Fasted training effects on  Body Composition












Figure 3: Effects on fat percentage in %.


Fasted training effects on waist circumference












Figure 4: Effects on waist circumference in cm.


Fasted training effects on  fat mass












Figure 5: Effects on fat mass in kg.


After the four week training period both groups had lost a significant amount of weight. In addition BMI and fat mass were both lower as well. There were no significant differences between both groups. Fat percentage and waist circumference did not change significantly.

What did the researchers conclude?

The researchers concluded that training on an empty stomach yields the same effects on body weight and body composition as exercise after a meal. Both are equally effective for weight loss. They did note that the small number of subjects and short study duration could have prevented them from finding small longer term effects on weight loss. A study employing a longer exercise period is necessary to confirm this however.

What does this mean for me?

-Fasted exercise is just as effective for losing weight and fat as training while fed.

See also:

-How to lose weight and fat effectively

-Tabata training

Described study:

-Schoenfeld, B.J., Aragon, A.A. Wilborn, C.D., Kriger, J.W., Sonmez, G.T. Body composition changes associated with fasted versus non-fasted aerobic exercise. Journal of the International Society of Sports Nutrition 2014, 11, 54.


-Ahlborg G., Felig P. Influence of glucose ingestion on fuel-hormone response during prolonged exercise. Journal of Applied Physiology, 1976, 41, 5 683–688.

-Civitarese A.E., Hesselink M.K., Russell A.P., Ravussin E., Schrauwen P. Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes. American Journal of Physiology, Endocrinol and Metabolism 2005, 289, 6, E1023–E1029.

-De Bock K., Derave W., Eijnde B.O., Hesselink M.K., Koninckx E., Rose A.J., Schrauwen P., Bonen A., Richter E.A., Hespel P. Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake. Journal of Applied Physiology 2008, 104, 4, 1045–1055.

-Horowitz J.F., Mora-Rodriguez R., Byerley L.O., Coyle E.F.: Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise. American Journal of Physiology 1997, 273, 4, E768–E775.