The new bestsellers are not talking about what you should eat to keep healthy, but when. Dr Mark Mattson, who has done research in ageing and neurodegenerative disorders, is among the pioneering proponent of the idea of intermittent fasting. He says, “If gourmet receptors are over activated they can actually kill neurons and that is actually important in understanding conditions such as stroke or brain injury…”
He explains, “The simple notion is that if you challenge yourself and your brain cells bioenergetically through exercise or fasting, nerve cells respond adaptively—and pathways are activated that increase neuronal resistance to stress and age-related neurodegenerative disorders.
Mattson says it is well known that if mice are given less calories, they live longer, but his experiment involved, “…subjecting animals to alternative day fasting, with a 10-25 percent calorie-restricted diet on the days in which they ate. If you repeat that when animals are young, they live 30 per cent longer,” says Mattson as he adds, “The animals’ nerve cells were more resistant to degeneration and functional outcome was better and faster as compared to animals that ate everyday.”
What then is the difference between consistently eating less and fasting? Mattson says, “If you eat three meals a day plus snacks in between, every time you eat the energy goes into your liver and is stored in the form of glycogen…it takes upwards of ten hours for us to completely deplete glycogen stores. So most people never deplete these stores. If you go longer, 12-16 hours of not eating anything, then you moblise fatty acids and they go into the blood, into the liver and are converted into what are called ketones and ketones are really very good alternative energy source for cells including neurons.”
Mattson’s lab had done an experiment where they had two groups of obese women, one on restricted calorie intake and the other group, almost fasting (eating only 500 calories) on two days of the week. The second group of women lost more weight because they were burning fat.
Mattson says, “There are three types of fasting regimens: the 5:2 diet; alternate day fasting (500-600 calories on “fasting” days); and time-restricted feeding, where you limit time window that you take in calories to six to eight hours…” Mattson demolishes some dietary “myths”, “Breakfast is the most important meal of the day; it’s necessary to eat three meals a day; it’s healthier to eat mini meals throughout the day than one or two big meals. “Largely this isn’t based on any good science that we can find.”
In this long talk with lots to learn, Mattson makes some other points which briefly are: ketones and physical exercise helps in diseases such as Parkinsons; breaking of fast after physical exercise clears the liver of glycogen more thoroughly, intermittent fasting increases autophagy; high protein diet is not good for ageing and finally, intermittent fasting may even slow down the progression of cancer.
