What triggers the motivation to eat?

People eat not only as they are hungry, but also because food just simply tastes too good to ignore.

New Delhi: It`s a well-known fact: people eat not only because they are hungry, but also because the food just simply tastes too good to ignore.

Now, a new study has helped explain how leptin, a hormone produced by fat tissue, influences that motivation to eat.

The study has been published in the August 6th Cell Metabolism, a Cell Press publication.

In the study, researchers have described for the first time a new bunch of leptin-responsive (LepRb) neurons in the brain`s lateral hypothalamic area (LHA). Those LHA neurons feed directly into the mesolimbic dopamine system seated in the ventral tegmental area (VTA) of the brain, which controls the rewarding properties we assign to things.

"Dopaminergic neurons in the VTA and their downstream targets represent the site of action for drugs of abuse, and also control motivation for food, sex or a fancy car," explained Martin Myers, Jr., of the University of Michigan, Ann Arbor. Put simply, "they control our wanting of stuff."

The study therefore adds to growing evidence that leptin doesn`t turn the appetite on and off just by controlling satiety – for instance, whether we feel hungry or full.