The Benefits Of Exercising Before Breakfast

Picture by Evan Bench from Flickr

How many of you don't eat anything before you exercise first thing in the morning? While I was still actively training I never went training first thing in the morning on an empty stomach. Definitely wouldn't be able to finish the session.

I still try to ride close to three hours most Saturday mornings and still cannot imagine not eating anything before the ride too.

So I was pretty surprised when I read that the benefits of exercising in a fasted state (up to 90 mins in the study) will significantly reduce the chance of you putting on weight if you've been eating like there's no tomorrow.

A group of healthy young men were recruited by researchers for their six week study. They were fed a diet of 50 percent fat and 30 percent more calories than what they had been consuming overall. What's more, some of the men agreed not to exercise during the six weeks (this is the control group).

The rest of the subjects were assigned to two exercise groups. Both groups did the same identical, supervised exercise four times a week in the mornings.  They ran and cycled at a strenuous intensity. Two of the exercise sessions were 90 mins, two were 60 mins.

One of the exercise groups ate a hefty carbohydrate rich breakfast before exercise and continued to ingest carbohydrates (in the form of sports drinks) during the exercise.

The other exercise group fasted before exercising and drank only water during the exercise.The second group did make up by eating similar amounts to the first exercise group later in the morning.

After six weeks the group that did no exercise put on an average of six pounds. What was worse was they had developed insulin resistance - their muscles were no longer responding well to insulin and had difficulty getting glucose out of their bloodstream efficiently.

Extra fat was stored between their muscle cells too. This insulin resistance and muscles stored with fat are metabolically unhealthy conditions that can be precursors of diabetes.

The first exercise group also gained weight, half as much as the control (non exercise) group. They too had become more insulin- resistant and were storing fat in their muscles.

Only the second exercise group did not gain weight and showed no signs of insulin resistance. They burned fat that they ingested more efficiently too.

The authors suggested that exercise training is more effective if have haven't eaten before exercise compared to eating a carbohydrate rich breakfast to stimulate glucose tolerance if you are on a high fat, high calorie diet. They explained that exercising in a fasted state (usually possible before breakfast) encourages the body to burn a greater percentage of fat (instead of carbohydrates) for fuel during vigorous exercise. Since you are utilising fat, you will not store it in your muscles.

This fasting group also had increased levels of a muscle protein that helps with transporting glucose in the bloodstream thus helping to regulate insulin sensitivity.

Exercising in a fasted state helped fight the two bad effects of eating a high fat, high calorie diet. Plus it prevented them from gaining weight.

Before you proceed to embark on your training sessions on an empty stomach do take note of the following caveats. Fasting before your race definitely won't work. You run the risk of "hitting the wall" during your workout since carbohydrates are easier for muscles to utilise than fat while exercising. The benefits more not be similar if you exercise at a more leisurely pace and for less duration.

A good time to adopt such a practice to fast before exercise is probably during the upcoming festive season (yes, it's already October, the year has flown by) where you indulge in more fat and calories than anytime of the year. Bear in mind the researchers detected that only three days of a extremely high fat and high calorie diet can lead to increased blood sugar levels and insulin resistance, potentially increasing your risk for Type 2 diabetes.

Running on a treadmill or cycling on the stationary bike in the gym is definitely safer if you plan to ride more than the 90 minutes (done in the study). You definitely don't want to bonk and fall while riding outside.

Reference

Van Proeyen K, Szlufcik K et al (2010). Training In The Fasted State Improves Glucose Tolerance During Fat-rich Diet. J Physiol. 588(21): 4289-4301. DOI: 10.1113/jphysiol.2010.196493.