Low-fat vs. Low-Carb: Which Diet is Best to Keep Pounds Off?
Want to know how to keep pounds off? A new study helps shed some light on what may work best.
We’ve said this before but it’s worth repeating: Losing weight is easier than keeping it off. That’s why national surveys show that only 1 in 6 adults that lost at least 10% of their initial body weight have kept it off for at least a year. To better understand why so few can maintain a slimmer self, researchers at Children’s Hospital Boston tested three different types of diets among adults who successfully lost weight.
The study, published this week in the Journal of the American Medical Association included 21 young adults who were overweight or obese at the onset of the study. All of the subjects were put on diets to lose 10 to 15% of their current body weight. Once they reached that point, they were randomly assigned one of the following diets for weight maintenance, while the researchers measured tracked their body weight as well as other biomarkers of health.
The three maintenance diets included:
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Low-Fat, High-Carbohydrate: 20% fat, 60% carbs (high glycemic foods included), 20% protein
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Low-Carbohydrate, High Protein, High Fat: 30% protein, 10% carbohydrate, 60% fat
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Low Glycemic Index: 40% carbohydrate, 20% protein, 40% fat. A balanced approach but with quality foods like minimally processed grains, fruits and vegetables. This is similar to a Mediterranean-style diet.
Low-fat vs. Low-Carb: Which Was Best?
The results found that subjects following the low-fat diet fared the worst. They burned the fewest calories during 24 hours and experienced hormonal changes that makes it easier to regain lost weight.
On the other hand, those on the low-carb diet burned about 325 calories more per day than those on the low-fat one, even though they consumed the same amount of calories on all these diets and exercise levels were kept constant among all three diet groups. However, while the low-fat diet seemed to provide a metabolic advantage for keeping pounds off, it increased markers of inflammation and cortisol, both of which may increase risk for heart disease.
The diet that provided the most health and weight loss advantages combined is the low glycemic-index diet. The subjects burned an additional 125 calories (the same calories burned from walking 1 ½ miles) compared to the low-fat diet and they had improved biomarkers for health. In addition the researchers say that it’s a diet approach that isn’t too extreme so you can follow it for life.
To me, this reaffirms that a calorie is not a calorie and we need to focus on the quality of the carbohydrates we eat to ensure that we don’t trigger a metabolic response from elevated blood sugar levels that makes it harder for us to lose and maintain a healthy weight.
For more about losing weight and keeping it off, check out these posts:
–Julie Upton, MS, RD
