It’s an ongoing debate in the nutrition world: Is one kind of diet—say, low carb or low fat—better than another for weight loss?
It seems like research comes out on the regular that’s in favor of one kind of eating, only to be overshadowed by another study that suggests the opposite. So, what’s a health-conscious runner trying to drop a few pounds to do?
Now, it looks there’s another wrinkle to add to the mix: The BMJ just published a report, which found that people who followed a low-carb diet burned more calories than those who consumed a high-carb diet.
But before you get excited, we’re here to tell you why you should take the findings with, er, a grain of…sugar.
What the New Low-Carb Study Found
In the study, researchers assigned overweight and obese people who had previously lost weight to one of three weight-maintenance diets: the first to a high-carb diet (60 percent of their diet from carbs), the second to a moderate-carb diet (40 percent of their diet from carbs), and the third a low-carb diet (20 percent of their diet from carbs) for 20 weeks. The protein for each group stuck to 20 percent.
At the end of the experiment, the researchers found that those on the low-carb diet burned 209 to 278 calories a day more than those on the high-carb diet. That translated to 50 to 70 calories a day for every 10 percent decrease in carbohydrate intake.
That’s not insignificant, says Heather Caplan, R.D.
People on the low-carb diet who had high levels of insulin secretion—insulin is produced after consuming glucose, the sugar found in carbs—burned even more calories: up to 478 calories a day.
Researcher David Ludwig, M.D., Ph.D., a professor in the department of nutrition at Harvard T.H. Chan School of Public Health, suggests this may be because insulin promotes fat storage and inhibits the release of calories from fat cells. Processed, fast-digesting carbs—white, refined carbs—are the most powerful when it comes to stimulating insulin secretion.
“People with high insulin secretion will be especially sensitive to high amounts of carbohydrate,” Ludwig, the director of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital, told Runner’s World.
The study also found that those on the low-carb diet had decreased levels of the hormones ghrelin and leptin, which inhibits insulin secretion and increases appetite, and regulates fat storage in the body, respectively.
“When your eating habits change so drastically like those in the study, there will be changes to the hunger hormones that we don’t entirely understand,” says Kelly Hogan, M.S., R.D., a dietitian in New York City.
So why might a low-carb diet be linked to increased calorie burn? While the overall nutrition field is split on this, the researchers think it’s because not all calories are equal and have different effects on the body.
“A low-carbohydrate diet, by reducing insulin levels, helps take fat cells out of storage overdrive,” says Ludwig. “With more fuel available for the muscles and brain on a low-carbohydrate diet, energy expenditure doesn’t drop as much following weight loss.”
Read more at: https://www.runnersworld.com