A body that is provided with food too often gets caught up in the maelstrom of a lack of exercise, obesity and ultimately diabetes. The trigger is a molecular switch that is controlled by insulin, a new study by scientists from ETH Zurich has revealed.
Eat breakfast like a king, lunch like a prince and dinner like a pauper. And nothing in between: no snacks, no sweets, not even anything we think of as healthy. For in order to stay healthy the body needs to fast between meals. At least this is what nutritionists would recommend were they to translate the results of a new study from ETH Zurich into practical terms. After all, the research group headed by Markus Stoffel, a professor from the Institute of Molecular Systems Biology at ETH Zurich, has discovered an important molecular mechanism that underlies a lack of exercise and therefore obesity. The researchers present their findings in the current issue of the journal Nature.
Hunger makes you active
The key switch player in this is a transcription factor called Foxa2. Transcription factors are proteins that make sure other genes are activated and converted into proteins. Foxa2 is found in the liver, where it influences fatburning, but also in two important neuron populations in the hypothalamus - the region of the brain 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.
If a person or animal ingests food, the beta cells in the pancreas release insulin, which blocks Foxa2. When fasting, there is a lack of insulin and Foxa2 is active. In the brain, the scientists have discovered, 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. "If you watch a cat or a dog before feeding it, you can see this very clearly", says Stoffel.
Explanation found for lack of movement