Surprising New Findings Indicate Low-Carb Diet May Not Aid Weight Loss—Experts Explain

• Eating a low-carb diet may not help you lose weight, new research finds.
• A study found that people who ate a meat-based low-carb diet gained more weight over time compared to those who followed a plant-based version.
• Experts explain the findings.

If you’re looking to lose weight, some studies point to cutting carbohydrates as a means to achieve your goals. But, new research finds that certain low-carb diets may not lead to weight loss.

A study published in JAMA Network Open examined data on over 67,000 people who participated in three separate studies. All participants in the three studies were considered healthy, under 65 years old, and had no pre-existing chronic conditions. Data was collected by participants self-reporting diet information and any weight loss or weight gain in four-year intervals.

Researchers compared the outcomes of those who followed five different types of low-carb diets, each reducing carbohydrates to about 38% to 40% of daily calorie intake. The study compared an overall low-carbohydrate diet to one that primarily used animal protein and fat; a second diet that focused on vegetable-sourced protein and fat; a low-carb diet that focused on eating less refined carbohydrates, more plant protein, and healthy fats such as olive oil; and finally, an “unhealthy” meal plan defined as one that included “unhealthy” fats, more animal protein, and refined grains.

The researchers found that the low-carb diets that emphasize the intake of high-quality macronutrients from healthy plant-based foods were associated with less weight gain, whereas low-carb diets that emphasize animal-sourced proteins and fats or refined carbohydrates were associated with more weight gain. These associations were more apparent among younger, heavier, and less active individuals.

To put it simply, people who ate a meat-based low-carb diet gained more weight over time compared with those who followed a plant-based version.

While there is no one universal definition of “low carb,” it’s typically considered to be a diet that limits carbohydrate-rich foods like grains, fruits, and starchy vegetables like potatoes, says Melissa Prest, D.C.N., R.D.N., national media spokesperson for the Academy of Nutrition and Dietetics and member of the Prevention Medical Review Board. “Most people following a low-carb diet will focus on choosing foods that are higher in protein, fats, and non-starchy vegetables like leafy greens,” she adds.

As for what a low-carb diet entails, Toby Amidor, M.S., R.D., C.D.N., award-winning nutrition expert and Sunsweet partner, says, “A healthier low-carb diet can consist of 45% of total calories from carbs which is between 900-1300 calories or 225-325 grams of carbs based on a 2,000 calorie diet.” This fewer-carb plan allows for a variety of carb-based whole foods to be consumed like fruit, whole grains, legumes, and dairy foods, so the body can get the nutrients it needs to stay healthy, Amidor explains.

Some low-carb diets cut back on carbs significantly, like the keto diet. “These are unhealthy low-carb diets as there is an inadequate amount of nutrients that are taken in to allow the body to stay at its peak health,” says Amidor.

Even though saturated fat, salt, and ultra-processed meats, like bacon, are considered low-carb foods, these options have been linked to inflammation, an increased risk of cancer, and heart disease, says Prest. “A better way to make a low-carb plate is by focusing on lean meats, unsaturated and monounsaturated fats like nuts or seeds, and choosing lower-carb vegetables like cauliflower, cabbage, leafy greens, and broccoli.”

Keri Gans, M.S., R.D., registered dietitian and author of The Small Change Diet, emphasizes that a low-carb diet does not equal a no-carb diet, “Remember that low-carb diets can, and should, still contain carbohydrates, especially those with health benefits.”

If you’re considering a low-carb diet, Gans says to consult a registered dietitian and/or primary care doctor to make sure you are still getting the nutrients your body needs. Amidor also notes that those with kidney, liver, gallbladder, and/or pancreas issues, especially those with types of diabetes, should consult a healthcare provider before starting to limit carbohydrates.

Madeleine, Prevention’s assistant editor, has a history with health writing from her experience as an editorial assistant at WebMD, and from her personal research at university. She graduated from the University of Michigan with a degree in biopsychology, cognition, and neuroscience—and she helps strategize for success across Prevention’s social media platforms. 

Source: prevention.com