Some people think performing a workout on an empty stomach burns more fat. However, researchers at Italy's University of Padua found that eating breakfast increased oxygen consumption and resulted in greater lipid utilization -- using fat for energy -- in healthy young men who exercised at moderate intensity, compared with exercising in a fasting state. They published their findings in the February 2011 "International Journal of Sport Nutrition and Exercise and Metabolism."
During exercise, your muscles use glycogen, a form of carbohydrate, for fuel. Insufficient fuel for exercise increases the risk of your body breaking down lean tissue for fuel. Losing muscle reduces your metabolic rate, impairing strength, exercise performance, weight loss and weight maintenance.
Eating a light breakfast before your morning workout provides energy you need to perform moderate to vigorous exercise. According to preliminary research findings from the 2011 Italian study, the body may burn more fat for up to 24 hours following a workout if you eat breakfast first instead of exercising on an empty stomach.
Consuming a low-glycemic breakfast increased fat oxidation during exercise and satiety during recovery, according to a study by University of Nottingham researchers. They published their results in the 2009 "Journal of Nutrition." The satiation factor is important, because people who work out with an empty stomach risk increasing their calorie intake later in the day. A low-glycemic food choice such as yogurt fuels your workout and curbs your appetite. Preliminary research indicates a low-glycemic meal results in greater fat oxidation than a high-glycemic meal, according to the British researchers.
Breakfast and Metabolism
Breakfast ranks as the most important meal of the day. It cues your body to increase your metabolic rate. When you sleep all your bodily processes slow down, including your metabolism -- your rate of burning calories. A low-glycemic breakfast provides sustained energy. A food's glycemic index provides a measure of the impact on blood sugar. High-glycemic foods such as white bread and sugary foods cause a rapid rise in blood sugar. Low-glycemic foods promote stable blood sugar. Eating yogurt and berries or eggs and whole grain toast provides a meal that fuels exercises without a blood sugar crash, compared with eating pastry or white toast.
Although you may burn some body fat working out on an empty stomach, consuming sufficient calories to fuel your exercise enables you to burn more calories overall. Your morning workout not only burns calories as you exercise. Exercise elevates your metabolism for up to 36 hours after your exercise session, the British researchers report. Consume a combination of protein and carbohydrates after your morning workout to replenish your muscles, such as low-fat milk and fruit or a quality protein drink. This aids in post-exercise recovery and reduces the risk of muscle loss. Consult your doctor before beginning a new exercise program.
- "International Journal of Sport Nutrition and Exercise Metabolism"; Exercising Fasting or Fed to Enhance Fat Loss? Influence of Food Intake on Respiratory Ratio and...; A. Paoli, et al.; February 2011
- "Journal of Nutrition"; Fat Oxidation During Exercise and Satiety during Recovery Are Increased following a Low-Glycemic Index Breakfast...; Emma J. Stevenson, et al.; May 2009
- Harvard School of Public Health: Carbohydrates: Good Carbs Guide the Way