Eat less for a long life
It has been found that calorie restriction (i.e. eating less) in mice:
- Extends life.
- Prevents rapid tumour growth.
- Makes the mice more active as well.
Anecdotally, the Okinawans of Japan, one of the world’s longest living and active populations, abide by an old saying, ‘hara hachi-bu,’ which translates roughly as ‘eat until you are 80% full.‘ Of course that is only an anecdote. In reality, they eat, on average, 11% less than the average Japanese diet.
How does that work?
It could be because, when you eat, your body produces insulin to metabolize carbohydrates and fats. Insulin also promotes growth. That means it promotes growth in malignant, i.e. cancerous, cells. Diet can change the growth environment of cells, including cancer cells. It changes the nurture, not the nature of cells. Diet does not contain carcinogens. It can just create an environment that cancer cells will flourish in.
If you restrict rats to 2/3rds of calories then they will live 30-50% longer. Why? Because they have less body fat? Because they have lower weight? No. Obese mice on a restricted diet live longer than non-obese mice on a non-restricted diet and the same as non-obese mice on a restricted diet.
Eating less is the thing, not leanness.
The popular answer is that it reduces the creation of free radical cells and therefore reduces the oxidation of cells and thus the opportunities for cancerous cells to develop. When food is scarce (i.e. when your body gets a signal that it is not eating a 100% diet) you live longer so that you will survive the starvation period and still be young enough to reproduce.
This may well be correct, but calorie restricted mice also have:
- Low insulin resistance.
- Low blood sugar.
- Low insulin levels.
- Low levels of Insulin-like Growth Factor (IGF).
Low-carb for a long life?
The glucose found in carbohydrates causes IGF and insulin levels to rise sharlply, in comparison to other food groups. So, in 2004, Cynthia Kenyon asked: could a low-carbohydrate diet lengthen lifespan in humans?
By reducing carbohydrates and glucose she was able to reduce:
- Blood pressure.
- Triglyceride levels (a fatty acid linked to incidence of heart disease and strokes).
- Blood sugar levels.
- And to increase levels of HDL (High-density lipoprotein, ‘good’ cholesterol).
While she is not able to conclude, after just six years, that a low-carbohydrate diet will lengthen the human lifespan, it seems to be promising data.
This article is based on the information found in The Diet Delusion by Gary Taubes (p218 onwards)