Can you fast for just a handful of days each month and drop pounds? Will cutting calories on those days help you live longer and fight disease?
Like many diet trends, intermittent fasting may sound too good to be true. But this concept, while not new, has been generating buzz as data starts to back up potential benefits beyond just weight loss. Most recently, a study in the journal Cell Metabolism showed intermittent fasting may decrease risk factors for diseases such as diabetes, cardiovascular disease and cancer, for example.
Can you do intermittent fasting? Should you do it? Start with the basics — and a conversation.
Good news: The answer is no.
“Fasting” may make you think of “starving.” But intermittent fasting is more about cutting way back on calories for short time periods. Doing so seems to affect your hunger and cravings over time.
The idea: As your body adjusts, you become satisfied more easily with smaller portions. And if you eat healthier foods throughout the process, you also reduce your craving for unhealthy foods, such as those loaded with refined sugars.
Intermittent fasting comes in many varieties. But a couple are the most common and best studied.
For example, the study above used an approach similar to a common five-day-per-month fasting diet. Each five-day period breaks down like this:
You may have heard of the popular “5, 2” plan, too. It involves reducing calorie intake for two days each week.
On fasting days, you eat two meals, the first around 200 calories and the second around 300 (equaling 500 for the entire day). On nonfasting days, you still follow a healthy diet (don’t switch to junk food), but you don’t have to restrict calories. You might think people pig out on those days, but over time, they truly do adjust to eating reasonably.
Even on fasting days, you get to eat real food: eggs, tomato-based soups, hummus and whole-wheat crackers, good fats like avocado. The key is how you mix them.
The recent Cell Metabolism study is one more bit of data suggesting the benefits of intermittent fasting go beyond weight loss. But weight loss is certainly a major benefit, too.
Previous research indicates fasting can have a beneficial effect on patients with diabetes and cardiovascular disease, help reduce cholesterol levels in certain conditions, affect the process of inflammation and even trigger stem cell regeneration.
There’s a lot of work being done in this field — but also a great deal left to be done to fully understand how and why fasting affects us.
Cutting way back on calories — even for short periods — can be a big change. Before you try it, speak with your doctor. You need to make sure you eat the right foods, especially on fasting days, for good health.
You also need to be sure no health concerns prevent you from fasting. People with a history of eating disorders, women who are pregnant or breastfeeding, children, and people recovering from surgery wouldn’t want to try intermittent fasting.
You might also wonder, “Can I do it?” People often fear mood swings, and honestly, you may have them — but just at first. Most people adjust quickly after the first few fasting days.
For example, one of my patients, 68-year-old Mary, has been doing an intermittent fasting diet for three months. She’s lost 21 pounds. Her lipid panel has improved, and so has her mood. She now says her two fasting days each week are easier than her non-fasting days.
That’s just one person’s experience. But now more research is backing up such experiences. If you’ve heard the buzz about intermittent fasting and wondered if it would work for you, a conversation with your doctor is a smart place to start.