“Shallow Hal” (Jack Black) may have seen the inner beauty in overweight Rosemary (Gwyneth Paltrow), but if you’ve worked hard to achieve a healthy weight, you want to see (and maintain) the results inside and out!

To do that, avoid refined carbs (white bread, white rice) and fatty meats (including all red meat). They deliver saturated fat and trigger blood-sugar levels that bounce all over, fueling cravings and making it harder to stay trim.

The healthiest way to keep weight off once you’ve lost it is not to slash all carbs or eliminate healthy fat. A low-fat diet (20 percent of daily calories) causes your metabolism to slow down, so you burn fewer calories a day than you would (with the same amount of activity) on a more moderate diet. A low-carb diet (10 percent of daily calories) may crank up the fat burn, but it raises stress hormone levels. That increases inflammation and your risk of heart disease, cancer and overall grumpiness.

So to keep from regaining weight, the winning formula is found around the shores of the Mediterranean: lots of unrefined carbohydrates (40 percent of calories from veggies and 100 percent whole grains), mono- and polyunsaturated fats (from olives, canola, avocados, walnuts, peanuts) and minimal saturated fat. Go easy on animal protein; make it from fish and skinless poultry. And do daily physical activity. Keep up a 10,000-steps-a-day habit.

Bonus: A consistent diet reduces rebounding. If you keep your weight loss off for two years, your chances of keeping it off forever skyrocket!

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is chief medical officer at the Cleveland Clinic Wellness Institute. For more information go to www.RealAge.com.