When Michael Catalano gets home from work, his kids are ready to wrestle.

"We would play that game for you know, 3 or 4 minutes, and would just be winded and tired and my energy level would just crash," said Michael Catalano.

Not anymore. He's found a way to boost his spirits and his energy… with food!

"Now you know, we can be in there and my wife has to yell at us to come in for dinner because we're in there playing so long," he said.

Seattle nutritionist Susan Kleiner is the author of "The Good Mood Diet."

"I hear 'I feel better than I've ever felt in my life, and oh, by the way, I've lost 8 pounds, 10 pounds, 12 pounds; so that doesn't even become their primary goal. How they feel is the most important, but of course weight loss is also important," said Kleiner.

This diet is not about deprivation.

"I want you to think about what you need to eat, not what you can't eat next," she said.

Start with three servings of dairy each day. Add a handful of nuts to keep serotonin levels high. Banish that mid-day energy slump with berries and high-fiber veggies.

Does it work? Just ask Mike.

"I feel so lousy when I fall off the wagon I can't wait to have that good feeling again, so I want to get back on the wagon," he said.

And yes, Dr. Kleiiner has an easy way to get you started.

"One of my top favorite foods in the whole program is the hot chocolate cocoa at night, before you go to bed, every night," she said.

Following the recipe is key.

"Nonfat milk, natural cocoa powder, so non-dutched cocoa powder and a little sweetener… so make that and it's a warm cozy ritual, that all by itself makes you feel better," she said.