This study, published in the BMJ, was one of the largest and longest one every to be done that analyzes at what rate the body processes calories based on different diets. During the study, once 164 overweight participants had lost 12% of their body weight, they were randomly assigned to three different diets: 

• A high carb diet (60% carbs, 20% fat and 20% protein)
• A moderate carb diet (40% carbs, 40% fat and 20% protein)
• A low carb diet (20% carbs, 60% fat and 20% protein)

 

The researchers adjusted calorie intake to keep their weight stable while keeping the carb intake consistent, and then they analyzed how many calories the participants burned.

Over the course of 20 weeks, the researchers provided every meal the 164 participants ate, so there was little room for error. (Compared to studies over just a few hours or days that rely on participants to record the food they eat.)

And it turns out that it wasn’t just about “calories in, calories out”, but the type of food your calories come from. The low carb group burned 250 more calories a day than the high carb group while still maintaining their weight, and participants with insulin resistance at the beginning of the study burned even more calories on a low carb diet… up to 478 extra a day. The low carb group also had lower levels of the hormone ghrelin, which regulates hunger.

This study shows that what you eat has an impact on your metabolism, and a low carb diet may have the biggest impact.

Processed carbs and hidden sugars raise insulin and trigger your body to store body fat, while healthy fats, moderate levels of protein and fiber-rich carbs that come from vegetables and low-glycemic fruits, and even some whole grains, don’t do this type of damage.

So this Christmas you can enjoy your turkey, mashed cauliflower, sautéed Brussels sprouts and other seasonal veggies knowing that research continues to support your low carb lifestyle.