What’s The Best Time to Lose the Fat?

By on September 1, 2015

If you’re changing your nutrition and exercise habits for the better two questions might come to mind. What’s the best time to exercise? And should I eat before exercise?

A 2010 study published in the Journal of Physiology is making the rounds on social media that might lead you to believe exercise before breakfast is your best bet. Let’s take a closer look at all sides of this discussion.

Subjects in the 2010 study were men put on hyper-caloric fat-rich diets. That is they ate 30% more than required calories and 50% of it was fat. Most of us considering the adoption of a healthy lifestyle would not choose either option.

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Three subsets of subjects exercised in either a fasted state (before eating), did the same amount and intensity of exercise after taking in calories or did no exercise. As you might guess, the non-exercise group gained fat weight during the study. The fasted state group did not gain weight like the group that ate prior to exercise did, but also did not lose.

The study does show hope for those who have glucose intolerance and insulin sensitivity. Yet it was targeting populations exposed to excessive dietary fat intake. If you have a heavy buffet schedule during the holidays and have ever considered just throwing in the towel until January, this study could sway you to reconsider. Fit in 20 minutes of exercise before breakfast several times a week and you might avoid holiday weight gain next year.

It’s important to note that exercise in the fasted state does markedly stimulate energy from fat oxidation. For those of us who aren’t over-indulging or insulin-sensitive however, there might be another consideration. Often the number of calories burned during exercise in a fasted state is lower and the exercise intensity is perceived as harder. That results in no more, and sometimes less, fat use when exercising fasted.

If you perceive exercise to be “harder” and less appealing, you’re less likely to stick with it. Many people can exercise longer and harder without perceiving it so when they have a pre-exercise snack. Yet, some individuals don’t tolerate much in their stomach prior to exercise. You may need to experiment to find out what works. Try easily digested foods like half a banana, or a small whey protein shake prior to exercise to begin.

Two additional studies (Obesity, 2013 and JISSN, 2014) testing fasted vs. fed state exercise both found no significant change. Weight and fat losses occurred at the same rate in both groups. One study looked at young adult females with a low-calorie diet and one looked at obese women who did not change their pre-study eating habits.

Back to the questions of when to exercise and should you eat before. The answer is if you’re skimping the improved nutrition part, early morning in a fasted state might help you avoid weight gain. Following an indulgent holiday dinner or during vacation week hitting your treadmill for a short but intense morning workout could keep the pounds off.

If you’re already watching your calories and eating sensibly there’s no science to say you’ll burn more calories all day. First thing in the morning you’re far less likely to be interrupted though.

Research results are specific to subject participants and conditions and can’t be generalized for other populations. In this case, the evidence seems to point to you. To eat or not to eat is up to you. To exercise early or later in the day is up to you. One thing is for sure, results happen under any conditions as long as you apply the most important ingredient: consistency.


  1. Van Proeyen, K. et al. Training in the fasted state improves glucose tolerance during a fat-rich diet. Journal of Physiology. Nov. 2010
  2. Schoenfeld, Brad Jon, et al. Body composition changes associated with fasted versus non-fasted aerobic exercise. Journal of International Society of Sports Nutrition. Nov. 2014
  3. Gillen, JB et al. Interval training in the fed or fasted state improves body composition and muscle oxidative capacity in overweight women. Obesity. 2013
Debra Atkinson, MS, CSCS – Founder & Barely Boomer, Voice for Fitness.

About Debra Atkinson

Debra Atkinson, MS, CSCS is America’s Boomer Fitness Expert, speaker, and author of Navigating Fitness After 50: Your GPS For Choosing Programs and Professionals You Can Trust. After 30years in the fitness industry Debra committed to making sure women have good choices, real answers and putting an end to the diet and exercise confusion. Her new book, The After 50 Fitness Formula for Females based on her women’s coaching workshops is due out in 2016. Visit Debra at www.voiceforfitness.com.

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What’s The Best Time to Lose the Fat?