You’ve heard the mantra: Eat frequently—five to seven small meals
daily, each including a serving of protein, healthy fat and
low-glycemic-index, or fibrous, carbohydrates, such as vegetables. Now
I’ve heard that maybe it’s a good idea not to eat those frequent meals
and instead engage in “intermittent fasting.” In a simple sense, most
folks think of this as basically not eating on occasion. And herein is
the problem. IF is different things to different people.
If people told me they were doing intermittent fasting, it would mean
that one or two days a week they simply didn’t eat. That’s fasting.
Fasting is not skipping dinner. It’s not skipping meal number four of
your six meals. Fasting is fasting. It’s not not eating
a meal. So until the International Group of Fasting Scientists come up
with an agreeable definition, it’ll be like judging a bikini contest;
it’s all in the eye of the beholder. That said, let’s at least look at
some telling statistics on what happens when humans alter their basic
patterns of eating.
A recent study from the International Journal of Obesity looked at
the feasibility and effectiveness of intermittent continuous energy with
continuous energy restriction for weight loss, insulin sensitivity and
other metabolic-disease-risk markers.1 In other words, the subjects
either cut their calories evenly over a six-month period or restricted
calories for only two days per week over the six-month period. Both
diets involved a 25 percent calorie restriction overall. The continuous
restriction group cut their calories by 25 percent spread evenly over
the week, whereas the intermittent group followed a very low-calorie
diet two days per week, cutting calories by 75 percent.
Results: both methods were equally effective for weight loss. Both
groups had similar reductions in leptin, free androgen index,
high-sensitivity C-reactive protein, total and low-density-lipoprotein
cholesterol, triglycerides, blood pressure and increases in
sex-hormone-binding globulin, IGF-binding proteins 1 and 2; however, the
intermittent group had a lower fasting insulin. So the bottom line is
that both seemed to produce similar weight loss, with the intermittent
method being better for insulin sensitivity. But that was in fat people.
What happens to folks who actually exercise?
In a more relevant study, scientists determined whether Ramadan
intermittent fasting affects 5,000-meter running performance and other
parameters classically associated with middle-distance performance.2
Ramadan is a month of obligatory daily fasting that starts at dawn and
ends at sunset, so that to me is “intermittent fasting.” Two
experimental groups participated in two experimental sessions, one
before Ramadan intermittent fasting and the other at the last week of
fasting. The subjects were 18 well-trained, middle-distance runners. At
the end of Ramadan fasting, a decrease in maximal voluntary
contraction—i.e. strength—was observed as well as a decrease in
performance of -5 percent. There was no effect on running efficiency or
maximal aerobic power. The study shows that Ramadan intermittent fasting
can result in a detriment to performance.
So should you fast or not? Or shall you stick religiously to six meals a day for the rest of your life?
Editor’s note: Jose Antonio, Ph.D., is the CEO of the International
Society of Sports Nutrition (www.theissn.org); also check out his site
www.TheWeekendWorkout.com.
1 Harvie, M.N., et al. (2011). The effects of intermittent or
continuous energy restriction on weight loss and metabolic disease risk
markers: a randomized trial in young overweight women. Int J Obes
(Lond). 35(5):714-27.
2 Brisswalter, J., et al. (2011). Effects of Ramadan intermittent
fasting on middle-distance running performance in well-trained runners.
Clin J Sport Med. 21(5):422-7.
TRAIN WITH WAYNE IS DEDICATED TO BRINGING YOU HEALTH INFORMATION WHICH YOU CAN STUDY AND PICK WHAT BEST WORKS FOR YOU AS AN INDIVIDUAL EXERCISER.
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