There have been a number of carb trends lately, from diets that cut way back on them (such as paleo, pegan, and keto) to carb cycling (a strategy that alternates lower-carb and higher-carb days). Now there’s carb back-loading, which—in a nutshell—entails eating most of your carbs at night.
The theory behind carb back-loading is based on the relationship between carbs and hormones like insulin and cortisol, which play a role in how likely you are to burn carbs or store them—either as glycogen (the carb “piggy banks” in your muscles) or as fat. Carb back-loading proponents believe that shifting the bulk of your carb intake, as well as your workout, to the evening optimizes hormones, and prevents carbs from being shuttled into fat cells.
All of this means that during the day you're limiting your carb intake to a very strict 30 grams, tops. The strategy is said to help reduce fat and build muscle, while you enjoy carby faves like pasta, bread, and sweets at night, after you've finished your workout.
But before you get too excited about ordering pad Thai for dinner, hold up. Here’s a closer look at carb back-loading, which isn’t as straightforward as it seems—and some bottom line advice about the best ways to eat carbs to manage your weight and maintain optimal health.
The evidence for carb back-loading isn’t all that promising
Without going into too much detail, the research is limited. Some studies cited to support the theory are either very small (with, say, 10 participants), or don’t follow the exact carb back-loading protocol. Other research relies on methods that aren't ideal, such as having participants report what they eat, or measuring body fat with techniques that aren't considered to be as accurate. And some studies were conducted with obese adults, who generally have different metabolic profiles and hormonal levels than active, normal weight people.
Carb back-loading is largely used by body builders
These people are engaged in intense workouts to build muscle mass and look extremely lean. If your objectives are to feel well, both physically and mentally; have a balanced relationship with food and your body; and optimize your nutrition, carb back-loading probably isn't for you. I also believe the eating strategy is risky if you have a history of disordered eating or binge eating.
The nighttime carb party does have limits
Fans of carb back-loading say it’s okay to enjoy fries, shakes, and desserts after workouts, and not worry about being gluttonous. But proponents also recommend that you aim for about one gram of carb per pound of body weight. So if you’re a 130-pound woman, you can't exactly enjoy an unlimited carb buffet. Case in point: one veggie burrito from Chipotle provides 123 carb grams.
When it comes to carbs and weight loss, extremes aren’t necessary
It’s simply not true that every gram of carb you eat will automatically feed your fat cells if you don’t limit your carbs to nighttime, after you've worked out. You can lose weight or prevent weight gain, and increase muscle mass by choosing quality carbs (think black beans, quinoa, oats, fruit and veggies) in appropriate portions.
Numerous studies back this up, and I see it over and over again in my practice. I’ve helped many professional athletes and others simultaneously reduce body fat and build muscle without using carb back-loading.
The truth is, many people overeat carbs, which creates a surplus of unneeded energy that either maintains body fat, or causes weight gain. And poor quality carbs, namely refined starch and sugar (think bagels and brownies), are even more likely to wreak havoc on your waistline.
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Simply upgrading the quality of your carbs (by eating more whole foods and fewer processed and refined foods) and eliminating your carb excess is enough to help you slim down. At the same time you’ll be supporting your energy, mood, digestive health, immunity, athletic performance, and overall nutrient intake.
Final thoughts: If you sit at a desk all day and work out in the evening, and you want to experiment with shifting your carb intake to later in the day, give that a try. But strive to create an approach that’s balanced, sustainable, and practical for your body’s needs. In my experience, this type of pattern yields the best results, both for your waistline and your overall wellness.
Cynthia Sass, MPH, RD, is Health’s contributing nutrition editor, a New York Times best-selling author, and a consultant for the New York Yankees and Brooklyn Nets.
Weight Loss – Health.com