According to a new study published in Nature by Markus Stoffel, a professor from the Institute of Molecular Systems Biology at ETH Zurich, you should eat breakfast like a king, lunch like a prince, and dinner like a pauper. And nothing in between. No snacks. In order to stay healthy the body needs to fast between meals, which runs counter to the nibble all day message peddled by many.
Hunger makes you active. The key switch player in this is a transcription factor called Foxa2 (I know, its a mouthful, but pay attention). Transcription factors are proteins that make sure other genes are activated and converted into proteins. Foxa2 is found in the liver where it influences fat burning, and also in two important neuron populations in the hypothalamus — the region of the brain (back of the head) that controls the daily rhythm, sleep, intake of food, and sexual behavior. The control element for Foxa2 activity is insulin, in both the liver and the hypothalamus.
When you ingest food, the beta cells in the pancreas release insulin which blocks Foxa2. When fasting or lacking food (think life among your ancestors), there is a lack of insulin and thus Foxa2 is active. In the brain, Foxa2 assists the formation of two proteins, MCH and orexin. These two brain messenger substances trigger different behavior patterns, the intake of food and spontaneous movement. If mammals are hungry, they are more alert and physically active. In short, they hunt and look for food. According to Stoffel, “If you watch a cat or a dog before feeding it, you can see this very clearly.”
The researchers also discovered that in obese mice the Foxa2 is permanently active, regardless of whether the animals are fasting or full. This may explain a well-known but until now unaccountable phenomenon: the lack of movement in obese people and animals. (Apologies to the keepers of the Christian moral tradition of sloth).
For Stoffel, the study clearly shows that, “The body needs fasting periods to stay healthy.” He therefore doesn’t think much of eating many little meals spread out over the day, but believes it is better to eat less frequently but well, and leave room in between to get hungry. After all, because insulin is released during every meal, thus suppressing Foxa2, the motivation to do physical exercise and burn sugar and fat visibly decreases. All of which is consistent with the “patchiness” of the food supply on the ancient landscape that selected our genome.
This is so frustrating. For every diet theory, there’s a counter-theory. Eat this way, no eat that way, never eat those foods, no, eat those foods all you want, stay away from these – count calories, don’t count, eat only when hungry, go hungry for extended periods… aargh! Everyone has studies to back them up, too. How’s a gal to know what’s best?
Wow, eye opening stuff. Most of the studies I’ve read advocate the exact opposite – eat many small meals throughout the day to keep your metabolism burning consistently.
Stoffel has a point in terms of human history though. Eating frequently wasn’t an option in the past. I’ll have to read more about this.
Marina – 2 keys to staying fit/healthy – get plenty of exercise and don’t eat processed food. Those are the 2 things that separate us from our ancestors.