Exercise - Timing Matters

I generally recommend exercise to all of my clients. Exercise promotes healthy weight, reduces cardiovascular disease, diabetes, cognitive decline and improves mood. But does the timing of exercise matter?

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In a recent study published in The journal of Endocrinology & Metabolism, researchers asked whether exercising in a fasting state produced greater benefits than exercising in a fed state. In this study, they randomized a group of overweight or obese men to exercise before breakfast, after breakfast, or not at all. 

Over the 6-week trial, not surprisingly, the men in both exercise groups lost more weight than the men in the control group. The amount of weight loss was similar for both exercise groups. On the surface, the results would appear to suggest that the timing of exercise did not matter. However, there were meaningful and significant differences between the groups in other health parameters. 

Those who exercised before breakfast burned double the amount of fat while increasing lean muscle mass during exercise compared to those who exercised after breakfast. They also benefited from reduced spikes in insulin after meals and improved insulin sensitivity. The muscles in men who exercised before breakfast showed increases in GLUT4, a key protein required for the transport of glucose into muscle cells. 

When the body is in a fasting state, it is apparent that several backup mechanisms ensure our muscles and brain get the necessary glucose for fuel. During exercise, after your body's glucose stores are exhausted, the body then taps into stored fat and turns that into glucose. This suggests that exercising when the body is already low on glucose may lead to more rapid fat burning.

This study offers additional compelling evidence that exercising before breakfast may provide more health benefits with the same investment of time and energy.