[adamduren]

Drugs that target the GLP-1 and GIP pathways can suppress appetite, potentially leading to a significant caloric deficit.

This can lead to the body to break down muscle tissue to obtain protein for energy which could lead to a loss of lean muscle mass

However, maintaining regular exercise and consuming sufficient protein can help to minimize the impact of lean muscle mass loss

[sjtgraham]

Protein is not what the body reaches for first in the absence of glucose/glycogen.

[sn9]

This is true but it's still extremely well established that you lose some muscle along with fat if you're in a prolonged caloric deficit without sufficient protein and strength training.