Eating a low-calorie, plant-based diet for five days reduces activity in two cellular signaling pathways called IGF-1 and mTOR, while increasing the cellular process of autophagy.

We analyzed the available evidence and found that 61 assertions support the idea that a five-day low-calorie plant-based diet reduces activity in the IGF-1 and mTOR pathways while increasing autophagy. No assertions in our review contradicted this. IGF-1 and mTOR are cellular signaling systems that help regulate growth and metabolism. When they’re less active, cells may shift toward repair and cleanup mode. Autophagy is the process where cells break down and recycle damaged parts — like an internal housecleaning. The evidence we’ve reviewed suggests that eating very few calories from plant sources for five days may trigger this shift. We did not find any studies in our analysis that showed the opposite effect. The 61 supporting assertions come from observations in human and animal models, lab studies, and metabolic tracking during short-term dietary interventions. These include measurements of blood markers linked to IGF-1 and mTOR, as well as cellular indicators of autophagy. It’s important to note that we’re looking at a very specific scenario: five days of low-calorie, plant-based eating. We don’t yet know how long these changes last, or whether they have the same effect in people with different health conditions. The evidence doesn’t tell us if this leads to better health outcomes — only that these biological signals appear to change during the diet. What we’ve found so far suggests that this kind of short-term eating pattern may influence key cellular processes in a way that aligns with repair and maintenance. For someone considering this approach, it may be worth exploring under guidance — especially since very low-calorie diets aren’t safe for everyone.