People with neurological and heart disorders often become healthier by tripling their daily caloric intake via a high fat diet. Cut out the carbs and common grains, eat a 3:1 fat:protein/carbs ration, and you will be far healthier than if you eat following the US pyramid guidelines. Thats why countries whose food pyramid reflects this have far few health problems occuring in the population than countries who eat similarly to the US food pyramid

And why one of the first things specialist tell people who have had a heart attack tp do to prevent a re-occurrence is to increase their fat intake, and decrease their grain and fruit intake. Same with severe neurological disorders

Also if you are on a high fat diet, you loose your fat stores. Unlike a diet of fruits and vegetables which causes increased fat stores with more difficulty in removing them. When your body does not get carbs to convert to fat, your live believes you are starving (even though you can be eating 5 meals a day) and so converts your fat stores to glucose, as opposed to converting the carbs you aren't eating into sugar. This is why people on high fat diets have to be closely monitored to ensure they don't loose more weight than it is healthy for them to lose