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Running on empty: can we chase the fat away?

Body composition changes associated with fasted versus non-fasted aerobic exercise.

Study under review: Body composition changes associated with fasted versus non-fasted aerobic exercise

Introduction

The idea of fasted cardio to accelerate fat loss has been, for the most part, based on a key assumption: with no food in our system, our fat stores are the go-to energy source, assuming low- to moderate-intensity cardio training. The use of fat is facilitated by the low levels of liver glycogen and insulin, and short-term studies suggest that fasted cardio does increase fat oxidation over 24 hours. It stands to reason that if done on a sustained basis, then there might be a greater amount of fat loss compared to if the training was done after eating breakfast or in the afternoon. But is this assumption correct?

Who and what was studied?

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What were the results?

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What does the study really tell us?

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The big picture

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Frequently Asked Questions

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Other Articles in Issue #03 (January 2015)