Doctors say we'll live longer if we exercise and eat right. Okay, but what does that mean, exactly? You hear so much about super foods and super diets that knowing how to “eat right” can be super confusing.

It doesn't have to be. Liz Applegate, a nutrition and fitness expert from UC Davis, has teamed up with Nugget Markets (a chain of nine markets which serve the greater Sacramento Valley) to present a “21-day Healthy Eating and Exercise Challenge,” an easy plan for making health a permanent part of our lives.

“This isn't about starving yourself or biting off more than you can chew at the gym,” Applegate says. “It's about making good-for-your-body decisions, rather than punishing you with cutting calories and tough-to-do workouts.”

Applegate teaches nutrition at UC Davis, including a wildly popular online and in-person nutrition course that attracts several thousand students each year. She's a triathlete, a sports nutrition columnist for Runner's World, an author of several sports nutrition books, director of sports nutrition for Intercollegiate Athletics at UC Davis, and a consultant for Olympic athletes.

In short, she knows her stuff. And when it comes to healthy eating, she says, don't over-think it.

“Eating well isn't about being perfect, but about finding out what food has to offer, and striking a balance between your needs, personal preferences, culture and family experience,” she says.

That philosophy is central to her healthy eating and exercise challenge, which you can pick up at any Nugget Market or download from its website here. Applegate's shopping list includes a wide variety of tasty foods — a bounty of fresh vegetables, various meats and poultry, fish, eggs, grains, dairy, chocolate and much more. What's not to like?

Even if you don't follow the plan to the letter, Applegate's general rules are manageable and straightforward:

1. Eat breakfast. A solid morning meal sets the stage for a good day of healthy eating.
2. Eat some protein at every meal to manage weight and support your exercise.
3. Whole grains like brown rice, quinoa and whole wheat are your friends (unless you cannot tolerate gluten. If so, stick with brown rice and other non-wheat products).
4. Aim for at least 2½ cups of veggies and 2 to 3 pieces of fruit each day.
5. Include healthy fats from fish, nuts and seeds. Use olive, canola or avocado oils.
6. Aim for 2 to 3 servings of calcium-rich foods like dairy or soymilk. Each day, eat a probiotic such as yogurt or kefir for digestive and immune support.

As for fitness, the plan provides a do-at-home circuit of strength training exercises, such as planks, push-ups, squats and leg lifts. Her general rules are:

1. Switch things up. You'll build stronger muscles when you try different types of exercises.
2. Aim for 30 to 60 minutes of moderate to vigorous activity five to seven days a week. Anything that boosts your heart rate counts — fast walking, jogging, bike riding, swimming, dancing, basketball, you name it. If you can't find time for 30 minutes straight, 10 minutes here and there will do the trick.
3. Include three to five do-at-home strength-building sessions that help shape and tone major muscle groups while building core strength.

Adjusting to healthy eating and routine exercise takes time, Applegate says, so don't be too hard on yourself.

The joy is in the journey.