Unprocessed red meat and weight loss: Is it a healthy choice?

New research reveals that unprocessed red meat can be safely included in weight maintenance diets, offering a high-protein boost without compromising metabolic health.

Study: Unprocessed red meat in the dietary treatment of obesity: a randomized controlled trial of beef supplementation during weight maintenance after successful weight loss. Image Credit: ajiilhampratama / Shutterstock

A randomized controlled trial of unprocessed red meat supplementation has been conducted at the University of Copenhagen, Denmark, to investigate the efficacy of intervention in maintaining weight after a successful weight reduction in obese people.

The study is published in The American Journal of Clinical Nutrition.

Background

Obesity is a chronic metabolic condition that has become a major public health concern worldwide. Several dietary interventions, including calorie restriction, have shown promising outcomes in terms of body weight reduction in obese people.
Despite effective weight loss, obese people often face challenges in maintaining weight after returning to a normal diet post-intervention. Evidence indicates that approximately 50 to 75% of the weight loss is regained within 3 to 5 years.

Higher reductions in metabolically active lean mass and resting energy expenditure are associated with worse weight maintenance in obese people. High-protein diets can limit these reductions and facilitate effective body weight maintenance post-intervention.

Red meat contains high amounts of proteins, accounting for 40% of all dietary proteins in developed countries. However, excessive consumption of red meat is known to increase the risk of cardiometabolic diseases. The adverse health effects of red meat have been linked to the type and quantity of consumption, with processed meat posing higher risks. Several clinical trials have indicated that unprocessed red meat consumed in amounts up to 150 grams per day is not associated with health adversities.

In this randomized controlled trial, scientists have investigated the effectiveness of unprocessed beef intake in maintaining body weight after a successful weight loss in obese people.

Trial Design

The trial included 108 obese healthy adults with a body mass index (BMI) of 28–40 kg/m². The total trial duration was 5 months, and it included an 8-week weight reduction period, followed by a 1-week period of reintroduction to regular foods and a subsequent 12-week period of weight maintenance.

To induce rapid weight loss, a very low-calorie diet with either standard or high protein content was implemented. For weight maintenance, an unrestricted (ad libitum) diet supplemented with either small (25 grams of beef per day) or large (150 grams of beef per day) amounts of beef was used. Participants were randomly assigned to these weight-maintenance diet plans.

The participant’s body weight, body composition, resting energy expenditure, and cardiometabolic risk factors were measured before the weight reduction period (baseline), immediately after the weight reduction period, and after the weight maintenance period.

Important Observations

The weight maintenance regimen included 80 participants who lost more than 8% of their initial body weight.

Both groups observed a reduction in daily energy intake and fat contribution to total calories compared to their usual intakes before weight reduction. An increase in lean mass and resting energy expenditure during the weight maintenance phase was observed in both groups, which is an important physiological finding. An increase in protein contribution to total calories and a decrease in carbohydrate contribution were observed among participants who consumed 150 grams of beef daily.

The average weight loss after the weight reduction period was 12.7% and 13% among participants who consumed 25 grams of beef and 150 grams of beef, respectively. Both groups observed reduced body fat content, fat mass, lean mass, visceral adipose tissue, waist and hip circumferences, waist-to-hip ratio, resting energy expenditure, and respiratory quotient after the weight reduction period.

After the weight maintenance period, body weight, fat content, fat mass, visceral adipose tissue, and waist and hip circumference continued to decrease in both groups. However, an increase in lean mass, resting energy expenditure, and respiratory quotient was noticed in both groups after this period.

Regarding cardiometabolic risk factors, both groups observed a reduction in resting systolic and diastolic blood pressure and fasting glucose and cholesterol concentrations after the weight reduction period. While these parameters rebounded slightly during weight maintenance, they remained significantly lower than baseline values, with some exceptions. High-density lipoprotein (HDL) cholesterol in both groups and low-density lipoprotein (LDL) cholesterol in the 150-gram-beef group returned to baseline values after this period.

After the weight reduction period, both groups observed a reduction in fasting insulin and triglyceride concentrations and an increase in the HDL-to-LDL cholesterol ratio, which remained unchanged thereafter.

After the weight reduction period, the 25-gram-beef group experienced a reduction in the level of glycated hemoglobin (a measure of glycemic control). However, it returned to the baseline values. No change in this parameter was observed in the 150-gram-beef group.

Study Limitations

The study duration of 3 months for the weight maintenance phase is relatively short, especially given that weight regain often occurs over several years. The dropout rate during the study was 36%, which could affect the generalizability of the findings. However, the results align with previous trials, offering insights into dietary strategies for short-term weight maintenance.

Significance

The trial findings indicate that diets with moderate or high amounts of unprocessed red meat have similar effects on body weight, body composition, energy metabolism, and cardiovascular risk factors among obese people during the first 3 months after rapid weight loss.

These findings suggest that unprocessed red meat has no adverse effects on body weight and metabolic function and can thus be included as part of a healthy diet for weight maintenance after a successful weight reduction in obese people. This study highlights the importance of adequate protein intake, whether from meat or other sources, in preventing weight regain and improving metabolic health.

The study’s funding from organizations linked to the beef industry, disclosed transparently, did not influence the study design or reporting.