This article makes a number of interesting claims about health and fitness, but I wanted to focus on this one:

In one International Journal of Sports Nutrition and Exercise Metabolism study, exercisers who ate breakfast before working enjoyed significantly higher VO2 (a measure of energy expenditure) and fat-burn rates compared to those who hadn't eaten breakfast before exercising.

  1. Can this be traced to a particular study which is not objectively problematic (e.g. retracted, published in a disreputable journal, rejected by a subsequent meta-study, etc.)?
  2. Is the study causal, or just correlational (i.e. did they passively observe, or actively assign people to control and treatment groups)?
  3. More generally, does the study support the claim that eating before exercising is more effective at burning calories and/or fat than eating after exercising?
  • @Dawn: I am specifically concerned with the boldfaced claim: If you're going to eat before or after your workout, do you burn more from eating before or from eating after? – Kevin May 21 '16 at 3:08
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  • That result doesn't sound very interesting. A body that is exercising + digesting food is bound to burn more calories than one that is only exercising. – Flimzy May 21 '16 at 11:13
  • @flimzy or, a body that isn't hungry can do better workouts. But still, there is no interestingness threshold for questions here, so it doesn't matter how boring anyone thinks this question is. – user30557 May 21 '16 at 17:34
  • A relevant video, but she lacks references. Essentially she says that your insulin levels are lower before you eat, but increases after you eat (decreasing your natural Growth Hormone [GH] levels). Since insulin helps to store body fat, and displaces your GH, exercising will be less "effective". – mrchaarlie May 26 '16 at 18:00

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