Exercise enthusiasts often wonder if it is best to eat before a workout or abstain. A new study published in March 2017 by the American Physiological Society (Endocrinology and Metabolism), which is the first of its kind, shows the effects of a meal and fasting on gene expression in adipose tissue (fat) In response to exercise.This study highlights the different roles played on fat in diet and response to exercise.
Researchers at the University of Bath (Great Britain) studied a group of overweight men.In a first test, the participants in this study walked for 60 minutes with a maximum oxygen consumption of 60%, with an empty stomach.Then, in the second stage, they walked for two hours after consuming a high-carbohydrate breakfast.The research team then conducted several blood samples for each stage of the tests.The researchers also collected samples of adipose tissue (fat mass) before and one hour after walking.
Do you have to stay fasting before physical activity and sports?
In this new study, gene expression in adipose tissue differed significantly in both trials. The expression of two genes, PDK4 ( Pyruvate dehydrogenase lipoamide kinase isozyme 4 ) and HSL ( hormone-sensitive lipase ) increased when men fasted and exercised, and decreased when they ate before exercising.The increase in PDK4 probably indicates that the stored fat was used to feed metabolism during exercise instead of carbohydrates from the recent meal.HSL generally increases when adipose tissue uses stored energy to support increased activity, such as during exercise.
These results reinforce the view that adipose tissue (fat mass) is often confronted with ” competing challenges “, researchers say. After eating, adipose tissue is busy responding to the meal and an exercise at that time will not stimulate the same beneficial changes in adipose tissue. This means that fasting exercise may cause more favorable changes in adipose tissue, and ” this could be beneficial to long-term health ” concluded the study.