Foods that have a high glycemic index (GI) like white bread, potatoes, and white rice are much more likely to increase the risk of weight gain following weight loss, according to a study in Diabetes Care.
Glycemic index measures the rate at which blood glucose spikes after a meal. The more dramatic that swing is, the more it’s associated with type 2 diabetes risk and weight gain overall.
In the recent study, researchers looked at data from a global study of over 2,000 people who were classified as overweight or obese. In the first phase, all participants consumed meal replacement shakes to achieve fast weight loss—the average drop over eight weeks was about 24 pounds.
In the second phase, conducted over a three-year time period, researchers compared two diets and two exercise strategies. One was a high-protein, low-GI diet while the other was a moderate-protein, moderate-GI diet, each of which was then combined with either high- or moderate-intensity exercise.
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All four groups regained some of the weight they’d lost initially, but those on the low-GI diet regained the least amount of weight. That led researchers to advise against eating potatoes, as well as high-GI bread options and rice varieties.
So, should you swear off these beloved foods forever if you don’t want to regain the weight you’ve lost? Maybe not, but limiting them could be key.
The problem here is that the study used such rapid weight gain as a result of a significant caloric deficit, says Shena Jaramillo, RD, dietitian at Peace and Nutrition. That means weight re-gain wasn’t dependent solely on the types of foods being reintroduced, but rather, simply going back to their previous calorie consumption.
“It’s important to note many people who experience rapid weight loss are following a low-carb diet,” she says. “When we reintroduce any carbohydrate, we’re going to see rapid weight gain. Much of this will be related to fluid shifts. As the study states, all groups in the experiment regained weight to some degree.”
That said, there is value in turning to low-GI foods but not simply because of blood glucose changes, Jaramillo adds. These foods generally tend to be higher in fiber, protein, or fat. That means you tend to eat less of them—because they’re more satiating—and that lowers your caloric intake overall, which can result in weight loss or weight maintenance. Plus, you get the numerous benefits that come with more fiber, like improved cardiovascular health and better digestive function.
“Even for someone who is diabetic, the total composition of their meal will have a much greater impact on blood sugars and total body weight than a single food, regardless of GI index,” says Jaramillo.
For more, be sure to read The Wrong Amount of Carbs to Eat Every Day, Says Dietitian.