Developed by John Kiefer, a physicist turned nutritionist, the carb backloading method makes dieting dead easy. It entails consuming proteins and fats throughout the day, then “carbing up” later in the day, often with fast-digesting carb sources such as cake (yes, cake!) in order to blast fat. The premise: When the body has few carbs throughout the day, the amount of glucose in the bloodstream is limited, so your body will draw on its fat stores for fuel.
At first glance, it seems a little reminiscent of the Hollywood Cookie Diet—you know, the one in which you eat four cookies per day and only one healthy meal? (Yeah, we must have missed that one, too!) But rather than starve your body of all nutrients except sugar for hours on end, the carb backloading approach takes advantage of the natural daily fluctuations in insulin sensitivity.
Research shows that insulin sensitivity is higher in the morning than in the evening, which means both muscle and fat cells are more receptive to carbs (glucose) earlier in the day. When you eat any carbs, either sugar or starch, your pancreas releases insulin to help your body utilize them. If you’ve just finished a workout, the insulin will help quickly shuttle the carbs plus the other nutrients you consume to your muscles to help repair and rebuild the tissue. Earlier in the day, the insulin will typically cause those carbs to become stored as fat. But if you steer clear of carbs as a fuel source throughout most of the day, blood-sugar levels remain low, so your body will burn more fat for fuel. Kiefer asserts that manipulating this effect is the key to burning fat while also creating an environment that’s conducive to muscle growth.
How it works: Upon waking in the morning, your body is in a powerful fat-burning mode. Eating can cause you to switch gears into a fat-gaining mode, proponents of the plan maintain. So skip this meal, fasting for at least two hours in the a.m. Contrary to popular belief, eating breakfast every morning does not give you a fat-burning edge. In fact, researchers from the University of Bath in the U.K. found no increase in resting metabolic rates of breakfast eaters compared with those of people who fasted every morning over a period of six weeks. And skipping breakfast didn’t prompt gorging later in the day, either.
Starting midmorning, Kiefer says to eat lightly, consuming only protein and fats for the majority of the day. Because you’re eating little to no carbs, there will not be much glucose in the bloodstream, so your body will draw on its fat stores for fuel. Then, after your evening workout (5 p.m. or later), begin consuming carbs in a post-workout meal; continue loading up on carbs throughout the evening. Choose fast-digesting carbs such as white rice, white potatoes, yams, sweet potatoes, and corn. Even sugar-laden junk foods such as cookies and ice cream are OK in moderation, say some fans of the diet.
“With weight training, muscle cells release glycogen [the stored form of glucose] for fuel,” explains Sara Fennell, a contest-prep coach and IFBB figure pro. “This causes glucose receptors to rise to the surface of the cell’s membrane and become very sensitive, looking for, and wanting, more glucose, so you can consume carbs without gaining fat.” Fennell follows up her workouts with a piece of cake and says that carb backloading was key to her success at the 2014 IFBB North American Championships, in which she earned her pro card—and achieved her leanest physique yet.
Keys to Carb Back Loading
Protein: 0.8-1.0 gram per pound of body weight
Carbs: (on training days): 50-150 grams
For maximum fat loss, keep carb intake closer to 1 gram per pound of body weight
Carbs (on nontraining days): 30 grams or less daily
Fats: 1.25 grams per pound of body weight.
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