In the quest for personal fitness, the best repetitions could be the ones you do with a fork. But lifting an Olympic barbell is easier than convincing athletes to pay attention to what they eat, says nutritionist Courtney Johnson, a strength and diet coach with CrossFit Oahu.

Her strategy is to create month-long nutrition throw-downs. They're sort of an eating dare and the prize is performance and better health.

Johnson's current challenge is a "paleo" diet. That's 30 days of unprocessed meats, fish, eggs, vegetables, fruit, nuts, seed and oils.

And no sugar, dairy, legumes, grains or alcohol.

It isn't an easy plan. When Johnson pitched it, a lot of folks wanted to know if they could get a "cheat day" for a birthday cake or a visiting relative.

She advised them to "get tough."

"Even if someone takes on 50 percent of this, it is way better than what they are doing now in most cases," she says.

IF YOUR ANCESTORS DIDN'T EAT IT ...

The meals need not be spartan. Coconut-encrusted chicken and fish and vegetable curry are two of Johnson's suggestions (see recipes, D5).

Identifying exactly what's allowed in a paleo diet isn't easy, but there's a simple philosophy, Johnson says.

"In the purest form, the theory of the paleo diet states that if your ancestors didn't eat it, you shouldn't either," she says.

Johnson's goal is to convince people to change their perspective on nutrition — and not just for a month.

"I know how hard behavior change is," she says. "It is something that needs to be sustainable but it also needs to produce results, or else you will not keep doing it."

A registered dietician, Johnson, 30, of Waikiki, divides her time between training sessions at CrossFit and her job as a "life coach" for people with diabetes at the University of Hawai'i's Center for Disability Studies. She also has a master's degree in public health and epidemiology.

'CHANGE YOUR LIFE'

At the CrossFit gym in Honolulu, Johnson often encounters members who embrace the exercise regime before they come to her for nutrition advice.

CrossFit routines mix strength and conditioning exercises in ever-changing combinations, stressing intensity and effort. It's been called "a fitness cult," says Johnson, who came to CrossFit with a background in downhill skiing and softball. Now one of her main pursuits is weightlifting.

She offers her month-long challenges to get people into a supportive, group environment. Her "Natural November" events stressed natural foods and have been popular among folks bracing for the holidays.

Johnson doesn't anticipate the paleo diet will produce dramatic losses in weight, but she does promise it will change your life.

"I think people will have a completely different outlook on how food and nutrition can change your life," she says.

"It can help with so many different ailments, from your sleep to your fitness results to your stress. Your mood. Your energy."

PALEO DISHES

Nutritionist Courtney Johnson offers these recipes for your paleo diet.

COCONUT-ENCRUSTED CHICKEN