What is "carb backloading," and does it actually work?
Carbs have been the topic of much conversation lately, especially as they pertain to weight loss. From the trendy keto diet, which forgoes carbs almost completely, to the concept of carb cycling, which allows people on low-carb diets to adjust their intake based on when their tougher training days are, there are lots of ways people are experimenting with their carbohydrate consumption.
One approach growing in popularity: carb backloading, the idea that eating all of your carbs later in the day can actually help you lose weight. To many who have followed the conventional diet wisdom of spreading carb (and calorie) intake out evenly throughout the day, this approach may sound totally off. So does it work, and should you consider trying it if you *love* eating carbs at night? Here's what nutrition pros have to say. (BTW, here's why healthy carbs definitely belong in your diet.)
What is carb backloading?
The most basic principle of carb backloading is simply eating most of your carbs later in the day. But to understand the rationale behind this approach, we have to talk about insulin and insulin sensitivity. "Insulin is like a key to your cells that helps transport and store energy that can be used by the body for fuel," says Emmie Satrazemis, a registered dietitian and nutrition director at Trifecta. Insulin increases, along with blood sugar, after you eat carbs. "'Insulin sensitivity' simply refers to how efficient this system is at any given time. Your body's insulin sensitivity is highest when you are craving carbs or energy the most, so after a period of fasting or after intense exercise."
So what does that have to do with carb backloading? "The theory of carb backloading is based on the fact that insulin sensitivity is higher earlier in the day, which promotes carbohydrate absorption into your muscles and fat tissue," Satrazemis says. Storing carbs in your muscle tissue is a good thing, since your body can use them as energy throughout the day and even during your workouts. Storing carbs in fat tissue isn't as desirable, she says, but that's part of the process.
"Carb backloading requires you to eat all of your carbs later in the day to promote using fat for fuel during the day, and suggests you also work out in the evening to promote better carb absorption into your muscles." By doing this, you can, in theory, lose fat faster, since you're mainly using fat as fuel during the day. (This is kind of similar to the idea behind the keto diet.)
But does carb backloading work?
Advocates of carb backloading point to research showing that eating carbs at night can help reduce appetite and ultimately help people lose weight. The only problem? "It is easy to prove just about anything looking at individual studies with small sample sizes," Satrazemis explains. In other words, just because something worked in a couple of small studies doesn't mean you should try it in IRL or that it's the only approach that works. "Currently, there is not enough evidence to show that when you eat carbohydrates affects your weight-loss capabilities," she says. "Without randomized controlled studies, much of this is just applied theory."
And in theory, carb backloading can be a good weight-loss strategy—in certain cases. "Carb backloading works best in two scenarios," says Mike Israetel, Ph.D., head science consultant at Renaissance Periodization.
"The first is for folks who exercise later in the evening. For them, eating carbs before and after their workouts helps optimize their muscle gains and recovery outcomes." That just happens to be at night. "The second scenario is for individuals who struggle with evening hunger during dieting, but really don't have as much of an appetite earlier in the morning. For them, eating more of their carbs when they are actually hungrier in the evenings can let them stick to their diet plan calories without driving them crazy with hunger or making them stuff food down in the mornings when they don't feel like eating."
As far as evidence that working out and eating your carbs later in the day is best for fat loss? "The evidence, taken on the net balance, is actually pretty equivocal as far as timing is concerned," Israetel says. "Especially for health, but for performance too." Essentially, carb backloading probably works, but not because it's better than other ways of timing your carb intake. More likely it's because it can help some people stick to their allotted amount of carbs (and other macros) for the day, or allows them to time their carbs around their evening workout, which makes most sense for nighttime exercisers.
Should you try carb backloading?
Maybe. "If you train later in the day and/or you struggle with hunger at night, it might be the right choice for you," Israetel says. "If not, then another timing option may be better."
There are some other limited cases when delaying carb intake until later in the day could be a good idea, although true carb backloading probably isn't necessary to achieve the desired results. "If someone came to me and told me that they get horrible GI distress when they consume anything before their morning run, I might suggest that they consume a moderate carb meal the night before, and wait until after their run to consume carbs again," says Edwina Clark, a registered dietitian and head of nutrition and wellness at Yummly.
"Similarly, if a type 2 diabetic or pre-diabetic client came to me with a long history of high glucose levels after consuming any carbohydrate in the morning, I might suggest that they wait until their midmorning snack to add in carb-rich foods." These are definitely isolated instances, though. "For most, I recommend spacing carbohydrate intake throughout the day, with particular emphasis on carbs before and after high-intensity exercise," Clark adds.
If you do decide to go for the carb backloading approach, know that quality and quantity still matters. "Whole-grain, high-fiber carbohydrate choices like whole-grain bread and pasta, quinoa, sweet potato, brown rice, oats, and beans assist with satiety, digestive health, cholesterol control, and more," Clark says. If weight loss is your goal, you'll definitely want to focus on these, along with keeping an eye on quantity.