Therapies aimed at areas of the brain responsible for memory and learning could lead to better treatment of obesity and dementia, says a study.

"This is a novel way for health care providers who treat people with weight problems and for researchers who study dementia to think about obesity and cognitive decline," said professor Terry Davidson from the American University in the US.

Researchers reviewed findings linking obesity with cognitive decline, including the "vicious cycle" model, which explains how weight-challenged individuals who suffer from particular kinds of cognitive impairment are more susceptible to overeating.

It is widely accepted that over consumption of dietary fats, sugar and sweeteners can cause obesity. These types of dietary factors are also linked to cognitive dysfunction.

Experiments in rats by the researchers showed that over consumption of foods high in saturated fats and simple carbohydrates can damage or change the blood-brain barrier, the tight network of blood vessels protecting the brain and substrates for cognition.

Certain kinds of dementia are known to arise from the breakdown in these brain substrates.

"Treating obesity successfully may also reduce the incidence of dementia, because the deterioration in the brain is often produced by the same diets that promote obesity," concluded the study that appeared in the journal Physiology & Behavior.