Getting fit and losing weight is supposed to make people feel great, but that isn't always the case. In many cases dieters deal with depression and mood swings caused by a change in the brain's chemicals brought on by the diet. The feel-good benefits of being fit and losing weight are taken for granted, but maybe they shouldn't be. Wendy weller says she dropped 50 pounds and was in for an emotional talk.

Wendy says "sometimes you wake up in the morning or go to sleep at night and you're a little depressed and you say to yourself, 'Why does this have to happen to me? Why can't I be like everybody else?'"Wendy is under the supervision of internist Dr. Louis Aronne at New Tork's Presbyterian hospital Weill Cornell.

He is one of the foremost weight loss experts in the country, and such complaints are very familiar to him. Weight loss specialist Dr. Louis Aronne says "the problem we've seen in low-lying depression and a problem with mood swings."

He says when dieters experience such feelings, it's not just in their heads, there is likely something metabolic going on. Dr. Aronne says "they are not getting enough carbohydrates for example they are not getting enough positive input from the enjoyment of food."

The doctor says this can directly affect dopamine and seratonin levels, the brain chemicals produce a feeling of well-being and the dieters may need to change their diet.

Dr. Aronne says "they're fatigued, lethargic, and kind of blue, we find if we add some carbohydrates usually at dinner time, they feel better, their mood improves."Wendy's goal is to lose another 25-50 pounds. She says to keep her outlook positive she also looks back.

Wendy says "I've accomplished a lot for myself, so therefore I reverse my mood swings, but you have to work at it, you really do."If you're dieting and you're thinking of adding a few carbs to your dinner, doctors suggest you make them high fiber carbs near the end of your meal for maximum benefit.