The discovery of another way in which the body appears to control how much it eats could shed fresh light on obesity. US researchers said poor diets may trigger a signalling system which prompts the body to consume even more.
When the signals - involving a protein linked to inflammation - were blocked in mice, they maintained normal weight.
However, a British scientist, writing in the journal Cell, warns that the discovery may not lead to new drugs because the protein may affect the immune system.
The link to obesity was made when scientists investigated "metabolic inflammation", a chronic, low-level condition often seen in obesity-related diseases. In mice, a protein connected to inflammatory reactions appeared to be switched on when the animals were given a high fat, high sugar diet.
Once the protein was switched on, the mice started eating more, suggesting that it was part of a pathway involving the regulation of food intake.
Closer examination of the the hypothalamus, which is known to be involved in energy regulation, revealed the protein present there too. In mice genetically altered to block the pathway, even with a high fat diet available, they were able to maintain a healthy weight.
