HOW MUCH MUSCLE WOULD YOU LOSE DURING STARVATION?
- 2 days ago
- 7 min read
Throughout evolution, humans have faced prolonged periods of food deprivation and have had to maintain their physical capacity to survive during these times. Therefore, the human metabolism has evolved to adapt to conditions of starvation. Today, however, fasting is mostly practiced voluntarily for weight loss or metabolic health purposes; its effects, particularly on muscle tissue and physical performance, are intensely debated. The significant decrease in body weight and lean body mass observed during fasting reinforces the perception that this process leads to muscle loss.
However, the concept of lean mass includes not only contractile muscle proteins but also muscle glycogen, intracellular water, and non-contractile proteins. Therefore, it is unclear whether a decrease in lean mass directly reflects changes in muscle function. While the metabolic effects of short-term fasting are well-defined in the current literature, the effects of longer-term fasting on the strength, endurance capacity, and muscle metabolism of large muscle groups have been investigated in a limited number of studies.
A study published in Nature Communications in 2025 comprehensively evaluates the effects of seven days of complete fasting on muscle strength, aerobic performance, and metabolic adaptations in humans. Furthermore, the study quantitatively analyzed how much of the observed lean mass loss during fasting corresponded to actual protein loss using urinary nitrogen measurements, and addressed the relationship between this loss and muscle function and strength using a holistic approach.
How was the study conducted?
PARTICIPANTS
The study included healthy, young individuals with prior exercise experience . A total of 15 participants were initially enrolled, but two were excluded from the analysis due to their inability to complete the fasting period. Thus, the study continued with 13 participants in total: 7 men and 6 women . Participants had no chronic illnesses and did not regularly take medication or use tobacco products. No serious side effects or clinical complications were reported during the study.
