Eating a low-carb diet based on meat? You may gain weight later on, study finds

By Sandee LaMotte, CNN

Published 11:00 AM EST, Wed December 27, 2023

If you want your low-carb diet to help you lose weight and keep it off, consider the quality of the food you eat, according to new research that compared five types of low-carb diets.

People who ate an unhealthy, meat-based low-carb diet gained weight over time compared with those who followed a heathier, plant-based version, the study found.

“When people consume diets that emphasize carbohydrates from whole grains, healthy non-tropical vegetable oils, and plant proteins, they have a better chance of keeping excess weight gain at bay,” said the study’s senior author Dr. Qi Sun, associate professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health in Boston.

Red and processed meat has been linked to cancer, heart disease, diabetes and more

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 healthy 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.

“To my knowledge, examining the effects on lasting weight loss of different low-carb variants is novel,” said Dr. David Katz, a specialist in preventive and lifestyle medicine who founded the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine. He was not involved in the research.

All of the diets reduced carbohydrates to about 38% to 40% of daily calorie intake. However, people who ate an unhealthy carb diet full of animal protein and fat gained weight long-term compared to people who focused on higher intakes of fruit, whole grains and non-starchy vegetables and lower intakes of dairy, red and processed meat, sugar-sweetened beverages, sweets and desserts.

Those who adopted unhealthy low-carb diets as a primary strategy gained, on average, roughly 2.3 kg, or 5.1 lbs., over 4 years,” said first author Binkai Liu, a research assistant in the department of nutrition at Harvard T.H. Chan School of Public Health.

“Those who adopted healthy low-carb diets as a primary strategy lost, on average, roughly 2.2 kg, or 4.9 lbs., for a mean, net difference between the two of 10 lbs.,” she said via email.

Large, high-quality studies

The study, published Wednesday in the journal JAMA Network Open, examined data on over 67,000 people who participated in three well-established longitudinal studies: the Nurses’ Health Study conducted between 1986 and 2010, the Nurses’ Health Study II, conducted between 1991 and 2015, and the Health Professionals Follow-up Study, conducted between 1986 and 2018.

“These are, of course, observational studies, and not designed to establish cause-and-effect; rather, they reveal associations,” Katz said. “However, when observed associations are potent, dose-responsive, hard to explain away and tethered to plausible mechanisms — cause-and-effect may at times be inferred.”

All participants in the three studies were healthy, under the age of 65 and had no preexisting chronic conditions. Weight loss or gain was self-reported at four-year intervals.

Low-carb diets that emphasized “high-quality macronutrients from healthy plant-based foods” were associated with less weight gain, the study noted, while low-carb diets that “emphasized animal-sourced proteins and fats or refined carbohydrates were associated with more weight gain.” The associations were more apparent among people who were younger, heavier and less active, the study found.

While the study focused on low-carb eating, the importance of food quality is key in any diet, said Sun, who is also director of the Nutritional Biomarker Laboratory at Harvard T.H. Chan School of Public Health.

“It is always wise to choose a diet (that) emphasizes fresh fruits and non-starchy vegetables, whole grains, nuts, legumes, olive oil and other vegetable oils, coffee, tea or just water, modest red wine if drinking, low sodium, and other healthy ingredients,” Sun said.

Eating a low-carb diet based on meat? You may gain weight later on, study finds

以肉为基础的低碳饮食？研究发现可能之后你会增肥

If you want your low-carb diet to help you lose weight and keep it off, consider the quality of the food you eat, according to new research that compared five types of low-carb diets.

根据一项对比了五种类型的低碳饮食的新研究，如果你希望低碳饮食来帮助你减肥并保持，你需要考虑下你吃的食物的质量。

People who ate an unhealthy, meat-based low-carb diet gained weight over time compared with those who followed a heathier, plant-based version, the study found.

研究称，与那些健康饮食、以素为基础的人相比，吃的不健康、以肉为基础的低碳饮食的人随着时间体重会增长。

“When people consume diets that emphasize carbohydrates from whole grains, healthy non-tropical vegetable oils, and plant proteins, they have a better chance of keeping excess weight gain at bay,” said the study’s senior author Dr. Qi Sun, associate professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health in Boston.

“当人们的饮食着重全谷物碳水化合物、健康的非热带植物油和植物蛋白时，他们更有可能控制体重增长”，该研究的资深作者、波士顿哈佛大学T.H.Chan公共卫生学院营养与流行病学副教授Qi Sun博士说道。

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 healthy 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.

该研究对比了整体低碳水化合物饮食与主要使用动物蛋白和脂肪的饮食；还有侧重于蔬菜来源的蛋白质和脂肪的第二种饮食；健康的低碳水化合物饮食，重点是少吃精制碳水化合物、多吃植物蛋白和橄榄油等健康脂肪；最后，一个不健康的饮食，定义为包含不健康的脂肪、更多的动物蛋白和精制谷物。

“To my knowledge, examining the effects on lasting weight loss of different low-carb variants is novel,” said Dr. David Katz, a specialist in preventive and lifestyle medicine who founded the nonprofit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine. He was not involved in the research.

“据我所知，不同低碳饮食对持久减肥的影响这个研究是新颖的”，预防和生活方式医学专家David Katz博士说道，他创立了非营利组织《True Health Initiative》，这是一个致力于基于证据的生活方式医学的全球专家联盟。他没有参与这项研究。

All of the diets reduced carbohydrates to about 38% to 40% of daily calorie intake. However, people who ate an unhealthy carb diet full of animal protein and fat gained weight long-term compared to people who focused on higher intakes of fruit, whole grains and non-starchy vegetables and lower intakes of dairy, red and processed meat, sugar-sweetened beverages, sweets and desserts.

所有这些类型的餐饮都将一天的碳水的量减少到大概每日卡路里的38%到40%之间。然而，与那些摄入更多水果、全谷物和非淀粉类蔬菜，更少乳制品、红肉和加工肉、含糖饮料、糖果和甜点的人相比，食用富含动物蛋白和脂肪的不健康碳水饮食的人长期而言增重了。

Those who adopted unhealthy low-carb diets as a primary strategy gained, on average, roughly 2.3 kg, or 5.1 lbs., over 4 years,” said first author Binkai Liu, a research assistant in the department of nutrition at Harvard T.H. Chan School of Public Health.

“那些主要基于不健康的低碳饮食的人，在4年内平均体重增加了约2.3公斤，即5.1磅”，第一作者、哈佛大学T.H.Chan公共卫生学院营养系研究助理Binkai Liu说道。

“Those who adopted healthy low-carb diets as a primary strategy lost, on average, roughly 2.2 kg, or 4.9 lbs., for a mean, net difference between the two of 10 lbs.,” she said via email.

“那些主要采用健康的低碳饮食的人，平均体重降低了约2.2千克，或者说4.9磅，这也意味着两组之间的净差距为10磅”，她在邮件中说道。

Large, high-quality studies

大范围，高质量的研究

The study, published Wednesday in the journal JAMA Network Open, examined data on over 67,000 people who participated in three well-established longitudinal studies: the Nurses’ Health Study conducted between 1986 and 2010, the Nurses’ Health Study II, conducted between 1991 and 2015, and the Health Professionals Follow-up Study, conducted between 1986 and 2018.

周三发表在《JAMA Network Open》上的这项研究，分析了超过67000人的数据，他们参与了三项经过确认的的纵向研究：1986年至2010年进行的护理健康研究、1991年至2015年进行的护理健康研究II和1986年至2018年进行的卫生专业人员随访研究。

“These are, of course, observational studies, and not designed to establish cause-and-effect; rather, they reveal associations,” Katz said. “However, when observed associations are potent, dose-responsive, hard to explain away and tethered to plausible mechanisms — cause-and-effect may at times be inferred.”

“当然，这些都是观察性研究，并不是为了确定因果关系，不过，它们揭示了一些关联”，Katz说道，“当观察到的关联是有说服力的、剂量响应性强、难以解释且与合理的机制相联系时，有时可以推断出其因果关系”。

All participants in the three studies were healthy, under the age of 65 and had no preexisting chronic conditions. Weight loss or gain was self-reported at four-year intervals.

所有这三项研究中的参与者都是身体健康，年龄在65岁以下，而且此前没有慢性疾病。他们每隔四年对体重增减进行自我报告。

Low-carb diets that emphasized “high-quality macronutrients from healthy plant-based foods” were associated with less weight gain, the study noted, while low-carb diets that “emphasized animal-sourced proteins and fats or refined carbohydrates were associated with more weight gain.” The associations were more apparent among people who were younger, heavier and less active, the study found.

研究指出，着重“来自健康植物性食品的高质量营养”的低碳饮食体重增加较少，而“着重动物来源的蛋白质和脂肪或精制碳水”的低碳饮食体重增加较多。研究还发现这种关系在那些更年轻、更健康和活动较少人群中更加明显。

While the study focused on low-carb eating, the importance of food quality is key in any diet, said Sun, who is also director of the Nutritional Biomarker Laboratory at Harvard T.H. Chan School of Public Health.

虽然这项研究的重点是低碳饮食，但食物质量在任何饮食中都很关键，哈佛大学T.H.Chan公共卫生学院营养生物标志物实验室的主任Sun说道。

“It is always wise to choose a diet (that) emphasizes fresh fruits and non-starchy vegetables, whole grains, nuts, legumes, olive oil and other vegetable oils, coffee, tea or just water, modest red wine if drinking, low sodium, and other healthy ingredients,” Sun said.

“着重新鲜水果和非淀粉类蔬菜、全谷物、坚果、豆类、橄榄油和其他植物油、咖啡、茶或水、适量红酒（如果喝酒的话）、低钠和其他健康材料的食材总是一种明智的选择”，Sun说道。