Intermittent Fasting: The Future of Fat Loss?

When it comes to getting leaner, six meals a day may become a thing of the past. The body of research on how intermittent fasting can speed fat burning continues to grow.

By Matthew Kadey, MS, RD | May 24, 2016

America has become a nation of snackers and around-the-clock eaters. But if you want to get ripped, and maybe even live longer, it could be a good idea to close the kitchen more often.

Intermittent fasting (IF) — defined as cycling between periods of restricted calorie intake and periods of normal consumption — is an eating pattern that dates back to our ancestral roots when food wasn’t always at arm’s length. This is in contrast to the more common (and some would say less sustainable) daily calorie restriction of typical diets, where people simply aim to reduce their everyday energy intake in hopes of banishing the bulge.

Far from a dieting gimmick, IF is a valid way to help people get their shred on, say more and more researchers. A 2015 study published in the European Journal of Clinical Nutrition found that IF reliably brings about weight loss — a safe rate of 0.5 to 1.7 pounds per week — along with improvements in body fat percentage. Similarly, when researchers at Baylor University (Waco, Texas) examined all available data, they found that alternate-day fasting of three to 12 weeks in duration effectively reduced bodyweight and body fat. And it may have lasting results: Scientists in Australia reported that eight weeks of research-controlled IF was not only enough to stimulate fat loss but it also kept much of the pudge at bay 44 weeks later when subjects were left to eat as they please. (Some researchers believe that IF impacts hunger hormones and teaches you to be more aware of the sensation of true physical hunger.)

There’s more good news. Research shows that IF has an adherence rate greater than most diets and does a better job at maintaining muscle mass. Other data indicate that a period of IF can improve heart health by lowering cholesterol, triglycerides, inflammation and blood pressure. It may also increase production of a longevity gene and help improve brain function as the years roll by. A reduction in both oxi-dative stress and inflammation might be why IF can keep your mind sharp.

So it’s good for your muscles, general health and gray matter. But how does intermittent fasting launch an all-out attack on your stubborn flab? It seems the major fat-torching benefit hails from improvements in insulin sensitivity within the body. As your cells become more attuned to insulin, the hormone that regulates blood sugar, your body processes food more efficiently, resulting in less risk of fat storage even when you eat more calories during non-fast periods. These blood-sugar benefits are one reason IF has gained interest as a diabetes foe.

IF also teaches the body to become more efficient at burning up belly fat for energy when faced with a shortage of carbohydrate stores. And since it can preserve existing muscle, there doesn’t seem to be a drop in fat-burning metabolism that’s typical of chronically low-calorie diets, which can rob the body of hard-earned muscle. Studies also show that most intermittent fasters don’t stuff themselves silly when tomorrow rolls around, which allows for a better overall calorie deficit. And just think: with less meal planning and food preparation in your schedule, life could become a bit less busy. Cheers!

Fast(ing) Five

Hungry for fat loss? Use these tips to get your fasting game on point.

1. Plan of attack

A popular IF plan is to eat as you normally would for five days a week and then restrict food intake to about 25 percent of a typical “feast” day, about 500 to 700 calories, on the other two days. This eliminates the misery of eating absolutely nothing on fasting days and makes IF more sustainable long term. Others might go calorie-free for one or two 24-hour periods each week. Another mini-fast method calls for restricting the daily eating period to eight hours, for example from 12 p.m. to 8 p.m., then you “fast” for 16 hours in between. If you want to ease into IF, you can try fasting in the evenings a couple of times a week, skipping dinner or eating something smaller like yogurt. Experiment to find which program works best for you and watch the pounds drop off.

2. Make it count

If your fasting routine involves days when you simply eat less, make those calories count by focusing on nutrient-dense, satiating foods such as whole grains, fiber-rich legumes, vegetables, fruits and fish. In other words, edibles that have lots of nutrients relative to the number of calories they contain. Also, drink plenty of calorie-free liquid when fasting to stay hydrated in the absence of water-containing foods.

3. Eat clean

You’ll only shed fat if you don’t use your non-fasting periods to binge. Your “normal diet” should be jam-packed with whole foods, not nutritional land mines. But IF can be more forgiving than many other diets, so don’t fret too much about how many calories you’re consuming.

4. Be patient

It can take a couple of weeks for your body to adjust to intermittent fasting. So if you experience side effects such as raging hunger, brain fog, mood disturbances (i.e. hangry) or low energy, there’s a good chance these will subside with time.

5. Keep pumping iron

Even on fasting days, you can still work up a sweat. In fact, studies show that short periods of fasting may not hinder exercise performance, and exercise can be a temporary appetite killer for some. Still, if you’re feeling very light-headed, step away from the squat rack.


About the Author

Matthew Kadey, MS, RD

Matthew Kadey, M.S., RD, is a Canadian-based dietitian, nutrition writer and recipe developer. A regular contributor for Oxygen and Muscle & Performance magazines, he is also the author of Rocket Fuel: Power-Packed Foods for Sports and Adventure (VeloPress, 2016), Muffin Tin Chef (Ulysses Press, 2012) and The No-Cook, No-Bake Cookbook (Ulysses Press, 2013). An avid cycle tourist, Matthew has pedaled his bike through Thailand, Cuba, New Zealand, Sri Lanka and Myanmar.