Let’s Eat?

Intermittent fasting may help you lose weight but it’s not a diet plan without risks or one that everyone should follow.

“You are what you eat.” Who hasn’t heard that line before, especially when discussing one’s health? Countless studies over many decades have demonstrated that the types of foods people eat affect their overall health—even influencing things such as the risk of getting certain types of cancer and helping prolonging life itself. What’s relatively new in the diet studies arena is a larger understanding that timing plays a part, too. Scientists are just beginning to understand that when you eat may also make a difference.

Going back a century or so, how and when people ate was much different than it is today. Blame technology for that. Refrigeration, rapid transportation, electric lights, smart phones—all have played a part in making food more readily available. The result is a big shift in eating patterns. Today, the average person eats throughout a 14-hour period each day. Researchers now believe that this constant intake of food can lead to health problems for many. Some studies suggest that fasting diets, the purposeful stopping of eating for a determined period of time, may have potential benefits.

Fasting diets mainly focus on the timing of when you eat. In time-restricted feeding, you eat every day but only during a limited number of hours. So, you may only eat between a six- to eight-hour window each day. In alternate-day fasting, you eat every other day and no or few calories on the days in between. Another type of fast restricts calories during the week but not on weekends.

While more research is being done on time-restricted eating, scientists really don’t know much about what happens to a body when a person fasts. Most research has been done in cells and animals in the lab. The work has provided clues as to how periods without food might affect the body. “In mice, we’ve seen that one of the effects of fasting is to kill damaged cells, and then turn on stem cells,” says Dr. Valter Longo, a National Institutes of Health longevity researcher. “Damaged cells can speed up aging and lead to cancer if they’re not destroyed. When stem cells are turned on, new healthy cells can replace the damaged cells.”

Now, studies are starting to look at what hap- pens in people, too. Some results have found that some types of fasting may have positive effects on aspects of health like blood sugar control, blood pressure and inflammation. Those are indeed healthy positives. For most people, though, the primary reason to try fasting is to lose weight.

“For some people, restricting calories every day may be the best approach. For others, it might be easier not to have to count calories every day and use an intermittent fasting strategy of weight loss,” says nutrition researcher Dr. Vicki Catenacci. “The best diet for any given person is the one that he or she can adhere to.”

Fasting may bring health benefits, but researchers caution that there’s still a lot we don’t know. Actually, for some, fasting may lead to problems. For example, some studies have found that people who regularly fast more than 16 or 18 hours a day have a higher risk of gallstones. Eating for 12 hours and then fasting for 12 hours is likely safe for most, says Dr. Longo. “That pattern of eating is very common among people who have record lifespans. It seems to match both science and tradition.”

Some studies suggest that alternate-day fasting can help with weight loss, generally being as effective as a low-calorie diet. That makes sense for most because reducing the number of calories one eats should help a person lose weight. But are there other health benefits one can attain through intermittent fasting?

To some extent, the simple answer is, yes. However, this is no onesize-fits-all idea. Losing weight and being physically active do help lower the risk of obesity-related diseases such as diabetes and some types of cancer. And, for these diseases, intermittent fasting seems to be about as beneficial as any other type of diet that reduces overall calories. In addition, some research suggests that intermittent fasting may be more beneficial than other diets for reducing inflammation and improving conditions associated with inflammation including Alzheimer’s disease, asthma, multiple sclerosis and stroke.

That said, before deciding to lock the refrigerator door tomorrow morning, be aware that suddenly changing one’s diet or going without food for a day isn’t an easy transition for most. Intermittent fasting can have unpleasant side effects like fatigue, insomnia, headaches and nausea. Plus, there’s that gnawing feeling of being really hungry. It usually takes about a month for most to adjust to the onand-off diet restrictions of short-term fasting.

So, while intermittent fasting is safe and ultimately healthy for many people, it’s certainly not for everyone. For example, skipping meals may not be the best way to manage weight for women who are breast feeding or are pregnant. Also, those who have kidney stones, diabetes or other medical issues will want to talk with a doctor before starting any kind of fasting plan. u