I am the first to admit that fasting sounds even worse than dieting. But some kinds of fasting can be easier than dieting—and have benefits that go well beyond weight loss. In fact, even people who are not overweight can get amazing benefits from fasting, including healthier hearts, stronger muscles and clearer thinking.
The technical term for what I’m talking about is “intermittent fasting,” which means fasting for short periods—sometimes, just 12 hours—on a regular basis. Most intermittent-fast techniques are not daily, and many allow for some calories even on “fast” days. This is definitely not a hunger strike! Some researchers believe that these intermittent fasts are easier to maintain than daily “caloric restriction”—aka traditional dieting, which basically requires that you eat less than you want every single day forever. Intrigued? Here’s more on the benefits of intermittent fasting and how you could easily try it…
WHY INTERMITTENT FASTING IS SO HEALTHY
Studies have shown that intermittent fasting can help people lose weight without losing muscle. Maintaining muscle is key to keeping weight off and healthy aging. People on intermittent fasts find it easier to control their appetite even on nonfasting days. One reason: They are producing less insulin, a key “hunger hormone.”
But there are many more benefits. These kinds of fasts have been shown to reduce blood pressure…reduce blood glucose levels and improve insulin sensitivity…reduce levels of triglycerides (blood fats) and improve the cholesterol profile…reduce inflammation…enhance muscle endurance…and even improve learning and memory. In animal studies, intermittent fasting can reverse type 2 diabetes, slow the progression of cardiovascular disease and prolong life.
Why is this kind of fasting so good for the body? One hypothesis is that our gut biome—the mix of gastrointestinal bacteria that’s key to health—needs a rest to function optimally. In addition, fasting has been shown to help the body get rid of damaged cells and regenerate healthy new ones. Humans likely evolved eating this way—food was scarce, and we couldn’t spend every day eating and snacking every few hours like we can now. Periodic fasting respects—maybe even resets—our internal body clocks.
CHOOSING A WAY TO FAST
The best fast is the one that fits into your lifestyle. Here are three options supported by scientific evidence…
Time-restricted eating. This is the easiest fast to pull off. Every day, you simply restrict eating to a specific stretch of the day. You’ll get the most benefits by limiting yourself to eating during just an eight-hour stretch—say, 10 am to 6 pm. But time-restricted eating is something you can ease into—for example, by restricting your eating to 12 hours…and then gradually scaling back to eight hours.
Eating at night, in particular, interferes with the body’s natural day-night cycle, disrupting hormones in a way that favors weight gain. And there’s psychology—choosing an endpoint to the day’s eating helps eliminate nighttime eating. Let’s face it: No one is sitting in front of the TV at night eating carrot sticks. It’s more likely to be ice cream or chips.
Tip: Get most of your calories early in the day, meaning you eat a big breakfast and a smaller lunch and dinner. It’s fine to eat breakfast several hours after you wake up—that’s healthy as long as it’s not paired with late-night eating.
Periodic fasting. On two consecutive days, you cut way back on calories—by 75%. The rest of the week, you eat in a normal fashion. The popular 5:2 Diet is an example of this approach.
Alternate-day fasting. In this approach, you alternate days when you restrict calories—to perhaps 500 calories for the day—with days when you eat a normal, healthy diet. This way of fasting is one day on, one day off. It’s effective, but some people find that they are too hungry on fasting days to sustain it.
Tip for periodic or alternate-day fasting: To meet your calorie goal and assure good nutrition on partial-fast days, make protein shakes with fruit and some form of healthy fat, such as ground flax or a no-sugar-added nut butter. A low-sugar plant-protein powder serves as the base. Two brands I like are Vega and Kashi GoLean (I’m fond of the Vanilla Vinyasa flavor).
Caution: Before you start any fast, discuss it with your health-care provider. That’s especially important if you have a medical condition. For example, although fasting may help improve diabetes, people who take blood sugar–lowering agents need to be especially careful about low blood sugar. Plus, some medications need to be taken with food.
More tips for successful intermittent fasting…
See a registered dietitian (RD). An RD can help you determine which of the eating patterns—if any—makes sense for you and help you put a plan into place. He/she can help you choose the most nutritious foods (especially important on days when you don’t eat as much as you normally do)…and, if you need them, recommend nutritional supplements.
Be extra wary when you eat out on partial-fasting days. Restaurants use more fat and sugar than you would at home, and portions are huge. It’s easier to eat at home so that you know what you’re taking in.
Consider professional metabolic testing. How can you know what to eat to cut calories by, say, 75%? You start by calculating the calories you burn at rest—your resting metabolic rate, aka RMR—and then add everyday activities plus physical exercise. Online RMR calculators are notably inaccurate. Better: An FDA-approved calorimeter, which measures your RMR when you breathe into it. These instruments are too expensive to make it worth buying one for home use, but many RDs have them in their offices.
“Cheat” with nonstarchy vegetables. If you find yourself extra-hungry on a fasting day, don’t suffer too much. The best way to “cheat” is with low-glycemic vegetables, many of which have lots of filling fiber and all of which have very little effect on blood sugar or insulin levels. Examples: Salad greens, cruciferous vegetables (broccoli, cabbage, cauliflower, etc.), radishes, zucchini, summer squash, eggplant, tomatoes and mushrooms. Bonus: These types of vegetables are especially good at feeding beneficial gut bacteria. One caution, though: Don’t pile on potatoes, winter squashes, corn, peas and the like—these are starchy vegetables that you shouldn’t cheat with.