Variants of the low-carb diet have been popular ways to lose weight, but a new study shows that it’s not just the amount of carbohydrates, fat, and protein that makes a difference in weight loss, but the quality of the food, too.
Research published on December 27, 2023 JAMA Network Openfollowed participants for decades to learn how five different types of low-carb diets affected weight.
“The most important takeaway from our study is that not all low-carb diets are created equal when it comes to long-term weight control; the quality of the food matters a lot,” says the study’s lead author, Binkai Liu, PhD. He is a research assistant professor of nutrition at the Harvard TH Chan School of Public Health in Boston.
Researchers found that a small portion of carbohydrates that are low in carbohydrates but high in quality protein, high in fat, and from healthy plant-based sources such as whole grains and beans are linked to slower weight gain. “On the other hand, low-carb diets rich in animal proteins and fats or refined carbohydrates, such as red and processed meat, dairy products, and sugar-sweetened beverages, can lead to faster weight gain,” says Dr. Liu .
“This study is great for helping to make clear that ‘low-carb’ is a crude term that involves oversimplification. There are many ways of eating that could be called low-carb,” says Dr. Christopher Gardner.
Dr., who was not involved in this study. The findings of this large, long-term observational study suggest that the only approach that clearly provides the greatest benefit to weight control is a healthy, plant-based approach, Gardner said.
Study Tracked Eating Patterns of 120,000 People Aged 30 to 40
Many studies have shown the benefits of cutting carbohydrates for short-term weight loss. Meta-analysis of 25 studies published April 2022 Diabetes, Obesity and Metabolism It found that low-carb diets were associated with “greater short-term weight loss compared to no-carb diets.”
However, this study aimed to fill the gap in knowledge about how effective low-carb is for long-term weight loss and whether nutritional quality matters. Using data from the first and second Nurses’ Health Studies and Health Professionals Follow-Up Study, researchers followed more than 120,000 healthy adults from 1986 to 2018.
Participants submitted self-reports about their diet and weight every four years through a survey of more than 130 food items, of which nearly 70 foods contained animal protein.
Researchers scored participants’ diets based on how well they fit into five low-carb diet categories, all consisting of 30 to 40 percent carbohydrates:
- Total low-carb diet focused on macronutrients, emphasizing lower carbohydrate intake overall
- An animal-based, low-carb diet with an emphasis on animal-based protein and fats
- A plant-based low-carb diet that emphasizes plant-based protein and fats, including sugar and refined white flour, both of which are plant-based
- A healthy, low-carb diet that emphasizes plant-based proteins, healthy fats, and fewer refined grains and added sugars
- An unhealthy, low-carb diet that emphasizes animal-based proteins, unhealthy fats, and carbohydrates from unhealthy sources such as processed breads and cereals
A Healthy Low-Carb Diet Was Better for Weight Loss
The study found that diets consisting of plant-based proteins, fats and healthy carbohydrates were significantly associated with slower weight gain over the long term than four other eating patterns.
People who followed unhealthy low-carb diets as a primary strategy gained an average of 5.1 pounds over four years, while people who adopted healthy low-carb diets as a primary strategy lost an average of 4.9 pounds; £10.
These associations were strongest in participants who were younger than 55, overweight or obese, less physically active, or a combination of these factors.
This study addresses an area of diet and nutrition that needs to be reviewed, says Julia Zumpano, RD, a registered dietitian at Cleveland Clinic in Ohio. “Popularity [low-carb diets] “It has increased over the past decade and initially focused on reducing carbohydrates by replacing them with meat and high-fat processed foods,” he says.
But these diets often lead to weight gain when the plan isn’t followed due to poor food choices and overly restrictive rules, says Zumpano, who was not involved in the study.
“I found the results to be confirming. “We need to focus on diet quality, minimize processed foods, and focus on whole foods and lean sources of protein from plant and animal sources,” he says.
Findings Complement and Confirm What Was Seen in Randomized Controlled Trials
This study is observational; So while it shows that a healthier low-carb diet is associated with weight loss, it doesn’t prove that eating a healthier carbohydrate diet causes positive effects.
Randomized controlled trials (RCTs) of dietary interventions are difficult to conduct, especially those lasting longer than six months, because participants are often unwilling to change the way they eat for more than a short period of time.
Still, the study is unique and valuable because it followed so many people for 30, even 40 years, Gardner says. This study addresses the most important issue: long-term and lifelong weight maintenance; This, it is said, could never be replicated in an interventional, randomized controlled trial.
“These findings complement many RCTs that have come to the same conclusion: diet quality, not just carbohydrate quantity, matters,” says Gardner.
Gardner is co-author of a 12-month randomized controlled dietary intervention published in November 2023. American Journal of Clinical Nutrition looked at people eating different types of low-carb diets. They also found that quality made a difference: The average drop in BMI was significantly greater in people eating a high-quality low-carb diet compared to a low-quality low-carb diet.
Expert Advice on How to Beat a Healthy Low-Carb Diet
Zumpano says low-carb diets can be very successful for weight loss and maintenance, especially when people consume a majority of plant-based foods. She recommends getting help from a registered dietitian to develop a plan specific to your needs.
She offers the following food suggestions to start a healthy low-carb life.
- Non-starchy vegetables (vegetables other than potatoes, peas, and corn)
- Protein sources such as beans and lentils and lean animal protein such as skinless poultry, seafood, Greek yogurt, cottage cheese and eggs, and limited red meat
- Small portions of whole grains such as quinoa, brown or wild rice, bulgur, or millet (1 cup cooked 1 to 2 times daily).
- Little to no processed foods or “low carb” baked goods.
- Plant-based oils in the form of extra virgin olive oil, avocado oil, avocados, nuts and seeds