From this article from haidut -- Cysteine/methionine restriction may treat obesity, without any increase in physical activity:
This finding is revolutionary for three reasons, all of which align perfectly with what Ray has been saying for years:
Methionine and cysteine restriction raises resting metabolic rate. This is the opposite of caloric restriction, which lowers metabolic rate. Raising RMR means the body naturally burns more energy at rest — the only sustainable way to lose weight without stress or deprivation.
The mechanism is metabolic, not behavioral. The mice did not eat less. They did not exercise more. They simply generated more heat — a sign of increased oxidative metabolism and mitochondrial efficiency. This is exactly what bioenergetics predicts: when you remove metabolic inhibitors (excess methionine and cysteine), the body functions better.
This is not about “plant-based” vs “animal-based” per se. The researchers note that vegetarians and vegans naturally consume less methionine and cysteine. However, the key is restriction of these specific amino acids, not avoidance of animal products entirely. Excess methionine and cysteine generate hydrogen sulfide and oxidative stress, which impair mitochondrial function. Restricting them improves redox balance and allows efficient energy production.
Here are some foods sorted by their tryptophan, methionine, and cysteine burden.
[image: 1782452539167-screen-shot-2026-06-25-at-10.41.31-pm.png]
