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Does Carb Backloading Help You Lose Weight? Science Says ...

"Eat carbs in the evening to lose weight!" "Avoid carbs in the evening to keep blood sugar in check!" Research into carb backloading is a mixed bag. What should you do?

By
Monica Reinagel, MS, LD/N, CNS
5-minute read
Episode #571
carbloading
The Quick And Dirty

Research showed that eating carbs mostly at night could aid in weight loss, but the devil is in the details!

  • Subjects on a very low calorie diet felt less hungry when they ate most of their carbs with the evening meal
  • Subjects eating a normal diet had poorer blood sugar control when they ate most of the carbs with the evening meal
  • Experiment to see how carb timing affects your appetite and quality of life

Tracy asks:

What are your thoughts about carb backloading? Some are touting the benefits of eating carbs only in the evening.

There is some research to support the benefits of eating most of your carbs at night. But as is almost always the case, the devil is in the details!

One study involved several dozen police officers, both men and women, all of whom were overweight. During the six-month study, the subjects followed a reduced-calorie diet. They all ate the same amount of carbohydrates—about 50 percent of their daily calories. But one group ate most of their carbs at lunch and the other ate most of their carbs at dinner.

At the end of the study, those who ate their carbs in the evening felt less hungry throughout the day. They also ended up losing a bit more weight and body fat.

Can carb backloading help you lose weight? 

It’s tempting to grab the headline here and run with it: Eat carbs at night and lose weight! But that summary, as appealing as it is, leaves out several key details.

The important thing to keep in mind here is that these subjects were eating a very low-calorie diet—just 1200 to 1500 calories a day.  As a result, they were losing weight fairly rapidly. (Something, by the way, that I do not recommend.) 

It’s tempting to grab the headline here and run with it: Eat carbs at night and lose weight! But that summary leaves out several key details.

Although they were saving up their carbs to eat at the evening meal, they were still eating a relatively small amount: one to two cups of rice or pasta, for example. It’s also important to note that the meal plans were devoid of added sugars, snack foods, and most processed foods. Also, the starchy foods were eaten at the evening meal, not as a bedtime snack.

But, within this context, eating starchy foods in the evening appears to have reduced hunger, which probably made it a little easier to stick to this regimen.

All of the subjects in this study saw improvements in their insulin and fasting glucose levels, which you would expect to see anytime you have substantial weight loss. But the group who ate most of their carbs in the evening had slightly greater improvements.

What if you’re not dieting, though? Is there any advantage to eating all or most of your carbs in the evening? Maybe not.

Does carb backloading improve blood sugar control?

A small trial of normal-weight men tested the effects of eating carbs early or late in the day without reducing the number of calories they ate. Not surprisingly, for those who had impaired glucose control to begin with, eating 300 grams of carbohydrate late in the day had an unfavorable effect on blood sugar metabolism. For those without impaired glucose metabolism, it didn’t seem to matter one way or the other. 

But notice that this effect is actually the opposite of the one seen in people who were losing weight. For them, eating in the evening led to slightly better blood sugar control.

If you’re envisioning a scenario where you eat a low-carb breakfast and lunch and then get a free pass to dig into a huge bowl of pasta followed by a few cookies and a big bowl of popcorn in front of the TV, I’m afraid I can’t help you there.

What do these studies tell us? They suggest that if you’re eating only healthful sources of carbohydrate (such as whole grains, legumes, or starchy vegetables) in very limited amounts, eating them in the evening might be beneficial. 

But, if you’re envisioning a scenario where you eat a low-carb breakfast and lunch and then get a free pass to dig into a huge bowl of pasta followed by a few cookies and a bowl of popcorn or pretzels to snack on in front of the TV, I’m afraid I can’t help you there.

Do carbs at night fight hunger the next day? 

According to the research I’ve reviewed, the only people who seem to get a benefit from carb backloading are those who are simultaneously dieting. And the primary benefit seems to be that it makes dieting a little less miserable by quelling hunger. A small but carb-rich meal late in the day stimulates the release of satiety hormones that decrease appetite the following day.

The only people who seem to get a benefit from carb backloading are those who are simultaneously dieting. 

But there’s another way to make dieting less miserable—not to do it! The dieters in these carb backloading studies were only eating 1200 to 1500 calories per day—about half of what the average adult eats.

And this approach to weight loss has a number of disadvantages beyond just daily hunger. When you lose weight this quickly, you tend to lose more muscle mass and less body fat. Second, you are more likely to trigger a metabolic backlash in which your body slows your metabolism to survive what it perceives to be an extended famine. And third, you are learning how to lose weight but not how to weigh less. As soon as you stop dieting, you're very likely to regain that weight.

If your goal is to lose some weight, I recommend a much more gradual approach. The slower you lose weight, the more it is likely to be body fat and the more likely you are to keep it off!

RELATED: The Case for Super-slow Weight Loss

 

How to experiment with carb backloading

If you want to experiment with carb timing, here’s how you might go about that:

If you’re only eating two to three servings of starchy foods a day, you could try saving them for your evening meal and see how it affects you.

  • How do you feel after your starch-rich evening meal?
  • How do you sleep at night?
  • Do you find that you get better appetite control the next day? (If you're trying to lose weight, this could be useful.)
  • Do you enjoy your daytime meals more or less without the starches?

These are things that no study can completely predict. But you can discover the answers with experimentation.

Just for fun, you might make your experiment into a crossover design. Follow your carbs-at-dinner protocol for a week and keep notes. Then, for another week, spread your carbs more evenly throughout the day. (This is known as a “washout” period; Rather than switch directly from one protocol to the other, you want to start each arm of your crossover from a relatively neutral state.) Then, for another week, eat most of your carbs in the first part of the day and observe how you feel.

To get the most accurate read, try to keep the type and amount of carbohydrates (and other foods) roughly the same throughout the entire three-week period.

The final step is to write and tell me what you discovered! You'll find Nutrition Diva contact info in my bio below.

About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show. 

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