Diabetes Drug Shown to Effectively Trim Fat With Minimal Muscle Loss: Study

Diabetes Drug Shown to Effectively Trim Fat With Minimal Muscle Loss: Study
A woman with diabetes takes an insulin injection. (Shutterstock)
Harry Lee
5/31/2023
Updated:
6/1/2023
0:00
Based on a recent analysis, Mounjaro, an approved medication for Type 2 diabetes, has shown promise in reducing fat mass without significant loss of lean mass, which can improve overall body composition. In contrast, popular weight loss drugs like Wegovy and Ozempic have been found to result in the loss of lean mass instead of fat.

The data showed that during a clinical trial of tirzepatide, the active substance of Mounjaro, participants experienced a reduction of 33 to 36 percent in fat mass and 10 to 11 percent in lean mass, varying based on age group. These findings indicate that lean mass was only a quarter of the weight lost.

The post-study analysis, published in the New England Journal of Medicine in July 2022, provides valuable insights into the substantial and sustained reductions in body weight that Mounjaro may offer.
The researchers did not explain why taking Mounjaro could lead to a more significant fat mass loss, and the underlying mechanism remains unknown.

Why Lean Mass Matters

Lean mass is the total body weight minus body fat weight, incorporating the weight of organs, skin, bones, body water, and muscle mass. During weight loss, body water and muscle mass are the two key components of lean mass to focus on since the weight of organs, skin, and bones remains relatively stable.

Lean body mass is closely associated with basal metabolic rate, determining the calories burned at rest. Consequently, losing lean mass can decrease metabolism, resulting in the body burning fewer calories.

Muscle has more mitochondria than any other organ, contributing to energy expenditure and calorie burning, according to Adarsh Gupta, medical weight loss practitioner and director of the Valley Forge Weight Management Center in Pennsylvania. “The more muscle mass you have, the higher your metabolic rate and, in other words, higher metabolism,” Gupta told The Epoch Times. “This helps you lose fat easily.”

Muscle Matters Even More as People Age

Loss of muscle mass is especially problematic for older adults. “As old people lose muscle, they become less capable of maintaining balance, among other things, and are at risk for falls, hip fractures, and head injuries, all with catastrophic consequences,” Dr. Mert Erogul, board-certified in emergency and obesity medicine, told The Epoch Times.
Research has indicated that in older individuals, a decline in muscle mass coincides with an increase in fat mass and is associated with a higher incidence of insulin resistance, potentially leading to various conditions such as Type 2 diabetes, obesity, heart disease, and osteoporosis.

How to Build and Maintain Muscle Mass

Muscle serves as a metabolically active tissue responsible for absorbing and storing energy, underscoring the significance of maintaining muscle for metabolic health, Erogul added. “Maintaining muscle is simply a matter of using it and feeding [it] with protein.” Protein is an essential component of the immune system, implying that an improved lean body mass can enhance the body’s ability to combat illness, infections, and stress more effectively.
Incorporating strength or resistance training into your routine can help retain muscle mass while increasing fat burning. As muscle mass increases, the body requires more calories during rest periods. A 2021 study (pdf) found that strength training promotes cellular changes that facilitate burning fat.

How Mounjaro Works

Mounjaro’s active substance, tirzepatide, is a single molecule known to suppress appetite by activating the body’s receptors for glucose-dependent insulinotropic polypeptide (GIP) and GLP-1, natural incretin hormones.
In comparison, semaglutide, the active substance in Ozempic and Wegovy, targets only GLP-1. All three medications require weekly injections. Ozempic and Wegovy, as sold in the United States, are manufactured by Novo Nordisk, a Danish pharmaceutical company, while Mounjaro is produced by Eli Lilly and Company, an American pharmaceutical company based in Indianapolis.
A randomized, active-controlled study conducted in 2021 found that tirzepatide was more effective than semaglutide regarding the average change in blood sugar levels and weight loss in Type 2 diabetes patients. However, it is worth noting that Eli Lilly funded the study, and the dosages of tirzepatide and semaglutide differed.
Although Ozempic and Mounjaro are currently approved for treating Type 2 diabetes, many people seeking weight loss have been requesting off-label prescriptions from their doctors.
Eli Lilly plans to seek approval for tirzepatide as an obesity drug, similar to Wegovy. This would potentially enable more people to access the medication through health insurance, despite its price tag of around $1,000 per month. The submission is expected to be completed in the coming weeks, with approval anticipated in late 2023.
In April, Eli Lilly announced the completion of the second phase 3 clinical trial for tirzepatide, known as SURMOUNT-2. The trial involved 938 adults who were either obese, overweight, or had Type 2 diabetes, demonstrating weight loss of up to 15.7 percent among participants.

Concerns About Mounjaro and Its Side Effects

Despite the remarkable weight-reducing effects of these drugs, some doctors express concerns about their side effects and the underlying mechanism of action.

“They essentially operate on the same mechanism as an eating disorder,” Lauren Muhlheim, a certified eating disorder specialist and clinical psychologist, told The Epoch Times, adding that people tend to lose weight because they eat less, not because the drugs magically burn fat.

Muhlheim cautioned that individuals who do not consume sufficient food may be at risk of binge eating later and developing anorexia.

Furthermore, research has shown that individuals who discontinued semaglutide regained two-thirds of the weight they had lost within a year. However, no similar study has been conducted regarding tirzepatide to date.

In the 2022 study involving 2,539 participants, the most commonly reported side effects were gastrointestinal disorders, including nausea, diarrhea, and constipation. Approximately 80 percent of participants receiving tirzepatide experienced at least one adverse event, compared to 72 percent in the placebo group.

Serious adverse events were reported by 6.3 percent of participants, totaling 160 individuals, with similar occurrences in both the tirzepatide and placebo groups. However, researchers believe approximately one-fifth of these events were associated with COVID-19. Additionally, the study recorded 11 deaths, with seven occurring in the tirzepatide group and four in the placebo group.

The U.S. Food and Drug Administration (FDA) has warned that Mounjaro may potentially elevate the risk of thyroid tumors (pdf). However, a definitive link has not yet been established. During clinical trials conducted on rats, tirzepatide exhibited a correlation between dosage and duration of treatment, leading to the development of thyroid C-cell tumors at clinically relevant exposures.
Moreover, in clinical studies, 14 cases of acute pancreatitis were confirmed by adjudication among 13 patients treated with the drug, according to the FDA. In comparison, there were three cases of acute pancreatitis among three patients treated with the comparator. It is important to note that Mounjaro has not been studied in patients with a previous history of pancreatitis.

How Other Diabetes Medications Impact Weight Loss

On the other hand, a 2021 double-blind study pointed out that semaglutide led to a more significant reduction in fat mass than lean body mass. However, it didn’t specify how much more significant the drop was. A 2020 study showed that after 52 weeks with semaglutide, total fat mass (baseline 33.2 kilograms) was reduced by 3.4 kilograms, and total lean mass (baseline 51.3 kilograms) was reduced by 2.3 kilograms.

Semaglutide is the active substance of Ozempic and Wegovy, hugely popular among people who want to lose weight. Wegovy has been approved to treat chronic weight management, while Ozempic is only for Type 2 diabetes patients.

“It is relevant to understand the effect of weight loss on fat mass and lean mass, particularly in the elderly. This new analysis shows that around three-quarters of the weight loss was fat mass, which is consistent across different ages,” said Louis Aronne, a professor at the Comprehensive Weight Control Center at Weill Cornell Medicine College in New York.

Aronne and colleagues presented the new analysis at the 30th European Congress on Obesity held in Dublin, Ireland, on May 17–20. The abstract has been peer-reviewed by the Congress selection committee.

Aronne, who has received funding from Eli Lilly, was among the authors of the 2022 study that received support from the same company.

Harry Lee is a New York-based reporter for The Epoch Times.
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