Meal planning was simpler for cavemen: Eat when you have food and run around looking for more when you don’t. For about two million years, that’s how it worked. And the human body evolved to thrive on a sporadic diet. For our ancestors, intermittent fasting was a way of life.

Cut to the present, where the biggest obstacle to food gathering is finding a good parking spot in the supermarket lot. Today, we are so overwhelmed with a variety of easily-accessible, palate-pleasing foods that we’re quite literally eating themselves to death, with nearly 40 percent of Americans obese, according to the Centers for Disease Control and Prevention.

Now, we struggle not to eat — particularly during the winter holiday season. But studies suggest that a vast majority of people who lose weight on diets put it back on – and then some.

Maybe it’s time to go back to our roots. Rather than count calories and avoid some of our favorite foods, we should just try not eating at all for designated periods of time.

That’s the philosophy behind intermittent fasting (IF), and studies through the years have found that this throwback dining schedule has a number of health benefits. Among them:

•    Reduced blood pressure.
•    Decreased fat mass.
•    Improved insulin sensitivity to fight diabetes.
•    Reduced oxidative damage to cells and DNA.
•    Lower inflammation biomarkers.
•    Improved brain health.
•    Greater autophagy, the ability of cells to eliminate waste and repair themselves.

“It’s only in periods where you don’t have food that your body goes into a sort of repair mode,” says Dr. Michael Mosley, a British physician and author of the best-selling book, “The Fast Diet: Lose Weight, Stay Healthy and Live Longer with the Simple Secret of Intermittent Fasting.”

“Some of the proteins get denatured. New ones get created. Your mitochondria cells originate. There’s a lot of fundamental biochemistry, which completely validates this argument.”

Brazilian have researchers found that IF not only has a “positive” metabolic effect in men but also that obese individuals have better luck sticking to an IF schedule than more traditional, calorie-restrictive diets.

“Deprivation kills consistency, and consistency is where your results come from,” says Brad Pilon, author of the IF tome “Eat Stop Eat.”

“If a diet isn’t sustainable, it isn’t going to work.”

Pilon recommends fasting for 24 hours once or twice a week, eating sensibly the rest of the time, and getting regular exercise. He even incorporates stout beer and mint chocolate chip ice cream into his menu.

“Give me a pint of Guinness at dinner and a bowl of ice cream before bed and I can be 100 percent on track with the rest of my eating for months and months,” he boasts.

Pilon’s program is called a “Periodic Fast.” Other variations include:

Lean Grains. Promoted by Swedish nutritionist Martin Berkhan, you fast 16 hours a day, but eat three meals during the other eight on the Lean Grains Diet. It’s said to be easy to maintain once you get into the rhythm. Like Pavlov’s dogs, your body knows when to start salivating.

The Warrior Diet. Eat just one meal a day. In a study published in the Journal of Clinical Nutrition, researchers compared a group of people who ate one meal a day to those who ate three. Although both groups consumed the same number of calories, the one-meal-a-day individuals showed a “significant” reduction of fat mass while building more lean muscle tissue.

Alternate Day Fasting. This is just what it sounds like. You eat pretty much all you want, but only every other day. It’s reportedly tough for humans to stick to but good for the lab rats in studies.

Whatever IF path you take, it seems likely to help you manage your weight, improve your general health and even awaken some of your primal instincts.

“Once you embrace the idea of intermittent fasting, you discover that your taste preferences change,” says Dr. Mosley. “You have greater control of your cravings, and that fear of hunger no longer dominates.”