Study: Semaglutide Reduces Cardiomyocyte Size and Cardiac Mass in Lean and Obese Mice

If you lost weight eating only fruits and vegetables, do you think some of that same tissue would shrink in size?

Today I learned that I my heart is a beast

This was in mice- keep that in mind and don’t bow to headlines and those with agendas

Semaglutide is actually anti catabolic

Glp-1 have shown to lower negative cardiac events and have shown significant reduction in all cause mortality

Glp1 aka semiglutide has been used for over a decade in humans without showing that side effect

Glp1 is naturally occurring hormone in the body and all you are doing is replacing natural levels and elevating slightly above high normal seen in the most lean individuals

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this study suggests that in those without heart conditions, reduced cardiac mass might have long-term risks.

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True, but for someone to lose a ton of weight, that risk is off set.

Also, the loss in muscle mass from weight loss can be offset with exercise.

I'm curious how they are measuring size reductions - is it just wet weight in a lab, are they isolating protein content, etc. You would assume things like glycogen stores would be reduced in these types of medications, although the heart does not store glycogen like skeletal muscle. I think the heart has about 1/5 the glycogen as skeletal muscle, by weight. Also curious if they do any cardiac assessments in the lab animals or in human studies, to see if ejection fraction changes, chamber size, etc.

From the university press release:
Dyck, who is the Canada Research Chair in Molecular Medicine and heads up the Cardiovascular Research Centre, says his team did not observe any detrimental functional effects in hearts of mice with smaller hearts and thus would not expect any overt health effects in humans. But he adds that there may be more impact over the long term, or some forms of cardiac stress may have a detrimental effect that wasn’t observed at rest.
The heart typical relies on fat for most ATP production, and does not use glucose as much. At high intensity glucose steps up, but so does fat, and the primary fuel for high intensity is lactate, via the lactate shuttle. Reductions in glucose wouldn't be expected to impact the heart unless there was some sort of maximal effort being induced, IMO. This is not a human study but it would not appear that cardiac changes are a red flag for otherwise healthy people - skeletal muscle changes could be a problem, though.

This was interesting:
Dyck’s study comes on the heels of a commentary published in the November issue of The Lancet by an international team of researchers from the U of A, McMaster and Louisiana State University who examined emerging research showing that up to 40 per cent of the weight lost by people using weight-loss drugs is actually muscle.
I didn't realize muscle loss was that pronounced with these meds.

Carla Prado, a nutrition researcher in the Faculty of Agricultural, Life & Environmental Sciences and lead author on the commentary, explains this rate of muscle decline is significantly higher than what is typically observed with calorie-reduced diets or normal aging and could lead to a host of long-term health issues — including decreased immunity, increased risk of infections and poor wound healing.

“Muscle does much more than just help us move or lift things. It is a powerful organ that keeps us healthy in a number of ways,” she says.

For example, muscle stores important building blocks — amino acids — that the body uses when we’re sick, stressed or injured to repair itself and stay strong. It also plays a huge role in managing blood sugar, which helps prevent diabetes.

As well, Prado notes muscle releases special molecules called myokines that signal other parts of the body to help fight infections and support our immune system.

“That’s why preserving muscle is so important, especially during weight-loss treatments — it’s not just about staying strong, but about keeping our whole body resilient and healthy.”

In the commentary, the authors suggest that muscle loss due to weight reduction may also exacerbate conditions like sarcopenic obesity — characterized by a combination of high body fat and low skeletal muscle mass — which contributes to poorer health outcomes, including cardiovascular disease and higher mortality rates.

I'm curious if nutrient timing and resistance training can offset this effect and result in a greater percentage of fat loss and more muscle preservation.

I think GLP-1 injections are a good “bridge” option. Take them for 6 months to a year while developing good habits and lifestyle changes-exercise, good diet etc.