What happens to brain-related chemicals when people don’t eat for 6 days?
Exploring the effect of prolonged fasting on kynurenine pathway metabolites and stress markers in healthy male individuals
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When grown-up men don’t eat for 6 days, their body changes certain brain-related chemicals. Some helpful ones go up, some harmful ones go down, and everything goes back to normal after eating again—even if they don’t gain all their weight back.
Surprising Findings
Cortisol didn’t increase despite 6 days of zero-calorie fasting
Most people believe prolonged fasting is a major stressor that spikes cortisol. This study shows the opposite—HPA axis remains stable.
Practical Takeaways
A 6-day fast may temporarily shift brain chemistry toward neuroprotection.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When grown-up men don’t eat for 6 days, their body changes certain brain-related chemicals. Some helpful ones go up, some harmful ones go down, and everything goes back to normal after eating again—even if they don’t gain all their weight back.
Surprising Findings
Cortisol didn’t increase despite 6 days of zero-calorie fasting
Most people believe prolonged fasting is a major stressor that spikes cortisol. This study shows the opposite—HPA axis remains stable.
Practical Takeaways
A 6-day fast may temporarily shift brain chemistry toward neuroprotection.
Publication
Journal
European Journal of Clinical Nutrition
Year
2024
Authors
Varvara Louvrou, Rima Solianik, M. Brazaitis, Sopie Erhardt
Related Content
Claims (6)
When you fast or eat less, certain chemicals in your body from the kynurenine pathway help your body respond in ways that keep you healthier for longer.
After a 6-day water-only fast, a man’s metabolism resets certain chemicals in his body back to normal within a week of eating again—even if he hasn’t regained all his weight yet.
If healthy guys don't eat for six days, their bodies show higher levels of certain chemicals linked to how the body handles stress and metabolism, with the highest levels seen right at the end of the fast.
Fasting for six days with no calories may lower certain chemicals in the blood linked to brain health — one drops because you're not eating, and the other suggests your body is producing fewer harmful substances.
If healthy guys stop eating for six days, their stress hormone levels don’t really go up — meaning their bodies don’t seem to treat it as a big stress event.