Unless you’ve been living under a rock for the past few years, you’ve probably heard of intermittent fasting: The latest ‘must-try’ diet trend that promises to curb hunger pangs and help you shed extra pounds.
Amid the deafening buzz of celebrity endorsements, it can be tempting to dismiss fasting as yet another ineffective fad. However, doing so might be a mistake.
Turns out, intermittent fasting is one fad diet that seems to be backed by real science. According to a review published by the New England Journal of Medicine, there are links between fasting and improvements in cognitive and physical performance, cardiovascular health, and symptoms of diabetes and obesity.
But—before you skip breakfast—it’s important to get the facts. We sat down with Zoom’s Doctor of Osteopathic Medicine, Dr. Benjamin Burton, to get some answers to your most burning intermittent fasting questions. Read on to hear his take on the dietary trend.
1. Hey Dr. Burton! Thanks for taking the time to talk intermittent fasting with us. Let’s cover the basics first: what is intermittent fasting?
Intermittent fasting is a diet philosophy that entails scheduling specific periods where eating will be significantly limited or avoided all-together.
Several different schedules can be incorporated with the intermittent fasting diet. One popular approach is to pick a couple of days a week where food is significantly restricted (something like eating only about ¼ of what you usually would need in a day) and then eating a normal, balanced diet the other days of the week.
The other approach is to pick a specific period every day to abstain from eating. This is often done in 12 or 16 hour periods. For example, only eating from 7 am to 7 pm daily and fasting for the remaining 12 hours. Or fasting from 11 am to 7 pm and fasting the remaining 16 hours.
2. Why is intermittent fasting so popular?
Dieting is intensely personal, and everyone has different needs. Making healthy food choices can be difficult, time-consuming, and exhausting for some. Sometimes, it’s just easier to decide to not eat at all for an extended period. This helps simplify things for a lot of people. For some people the eating pattern is much more intuitive and easier to follow.
Fasting is gaining popularity in the medical field because there is some evidence that there are a number of health benefits beyond just weight loss. It seems to have additional value in preventing or treating diabetes. Most weight loss programs improve blood sugar, but intermittent fasting can potentially improve blood sugar before a significant amount of weight is lost.
3. Is it safe?
Intermittent fasting, as it is laid out in most mainstream programs, is quite safe. As with anything, if taken to an extreme can become unhealthy. Generally, fasting for more than 24 hours should be done with caution, and fasting for more than 72 hours should be avoided. In any fasting scenario, it is important to stay hydrated. I recommend that most periods of fasting be a “water fast,” meaning abstaining from food but still drinking water. This allows for the benefits of a caloric restriction but protects against dehydration.
4. Are there any myths about intermittent fasting? If so, what are they?
I’m not sure there are many myths, but there are some claims that are not fully scientifically validated yet. These include claims that intermittent fasting will improve sleep, prevent dementia, and prevent cancer. These claims may all be true, but we haven’t fully validated these claims in human research.
5. Are there side effects?
Food provides essential glucose and electrolytes (like potassium and sodium) that we need on a daily basis. The human body has mechanisms that monitor and maintain normal levels of glucose and electrolytes even when a person isn’t eating. However, people that take medications that affect blood sugar (diabetes medication) or medications that affect electrolytes (mainly blood pressure medication) should discuss fasting with their doctor before starting. There are also rare diseases that would prohibit some people from fasting, but generally, these individuals are well aware they should avoid fasting.
6. What are the benefits of intermittent fasting?
The biggest benefits that are currently well-validated are weight loss and improved blood sugar control.
7. Will fasting improve overall health?
Intermittent fasting certainly has the potential to improve health. For many people, losing just 10% of their excess weight can result in significant health benefits.
8. Is there a right or wrong way to intermittently fast?
Dieting is an incredibly personal thing. I recommend beginning with a well established intermittent fasting routine. Once a person is comfortable with that, they can try modifying it a little to suit their life situation better. I would discourage extreme fasting for most people. (e.g., fasting beyond 24 hours).
9. Is intermittent fasting for everyone?
No, a hundred times no.
If anyone could find a diet that is safe and effective for the majority of the population, they should get a Noble Prize. Intermittent fasting requires a lot of meal planning and diverging from traditional mealtime routines. It is hard for some people to do this in a typical 8-hour workday if they don’t have a lot of flexibility regarding meal times. There are a lot of other barriers that can really make this program difficult.
10. How many days, if any, are recommended to intermittently fast each week?
There are several different programs. The most popular one currently is a daily 16:8 routine where a person fasts for 16 hours and eats for 8.
11. Is intermittent fasting an effective form of dieting?
It can be. The value of any diet program is calorie restriction and food tracking. Intermittent fasting seems to really click for some people and help them control their food intake.
12. Will intermittent fasting promote weight and/or fat loss?
Intermittent fasting has been found to promote weight loss.
13. Will intermittent fasting put the body into starvation mode?
The “starvation mode” is an interesting theory, and maybe a myth in first world countries. There is an unhealthy starvation state that is achieved with extreme starvation. This requires a level of food deprivation that is generally only seen in severe poverty or inhumane treatment of prisoners. Some diet philosophies like frequent small meals to “keep the metabolism going” or restricting too much and putting the body in a “starvation mode” aren’t really well validated. More likely, people that over restrict put themselves into a restrict/binge pattern. While these people have periods of little food intake, they then slip and binge, thus overeating in the long run. Intermittent fasting directly challenges these “starvation mode” theories, and to some degree, seems to discredit them. Finding the right balance is tricky. It is important to monitor and be purposeful about eating. There is a difference between intermittent fasting and a binge/restrict pattern of eating.
14. What is the protocol on exercise while intermittently fasting?
Exercise, like dieting, is intensely personal. Intermittent fasting is generally used to lose weight. Exercise programs targeted at weight loss would be congruent with intermittent fasting. If someone is exercising to train for an endurance activity or gain muscle mass, intermittent fasting can be used, but this would require a high level of planning and coordination. This would require a lot of individualized research and maybe coordination with health professionals like trainers and nutritionists.