When You Eat Is as Important as What You Eat

For weight loss and appetite control, fasting may work better than dieting

Intermittent fasting has been in the news lately, but can this variation on an ancient practice really help with weight loss? And should you consider it?

While fasting as a concept has been around for millions of years and embraced by many cultures, we are just starting to learn about the medical benefits.

On an evolutionary level, our bodies may have adapted to this feast or famine mindset when food was not readily available 24 hours a day. During times of fasting the body is forced to first break down stored sugar and then start breaking down stored fat. This can lead to weight loss. It may also lower appetite and curb those late night cravings.

So, if you are struggling to restrict your calorie intake or are tired of trying fad diets, intermittent fasting may be a good option.

What is intermittent fasting?

Fasting is a way to reduce calories. Unlike a diet, however, it does not restrict what you eat, but only the times when you are actually eating. For many of us, what we like to eat is relatively fixed, which is why calorie restriction can be so tough. But having a limited time to eat forces us to eat less without depriving us of foods we enjoy. In addition, some people feel that having a time limit on their eating leaves them time to do other things and not have to think about their next meal or food preparation.

How do you do it?

First, you have to prepare yourself mentally that you are not going to eat at all for a certain period of time each day. There are several versions, which can be adapted to your lifestyle. One plan is called the 16:8 plan where you have an 8-hour window each day in which to eat and you fast the other 16 hours. Timing can be customized. If you prefer to not eat until noon, then you have until 8 p.m. to finish dinner. Those who need or prefer to consume their first meal of the day before noon will have an earlier dinnertime.

Importantly, daily intermittent fasting does not allow for late night (post-dinner) eating and reduces the opportunity to make poor food choices. For many of us, nighttime snacking is where the calories add up because that is when we tend to do more emotional eating, and choose foods high in calories and sugar

Another variation is the 5:2 plan, where five days are regular eating days and two days are ‘fasting’ days, when the goals is to consume around 600 calories a day or less. The fasting days do not have to be consecutive.

There are other forms and variations of these two plans, which can be adapted to your eating pattern and lifestyle.

What are the benefits?

As the body gets used to fasting for short periods, your appetite lessens. And a growing body of research suggests that intermittent fasting can improve control of glucose levels and the management of diabetes. We are also learning more about possible benefits at the cellular level. In addition, any of my patients who try intermittent fasting report having more energy, focus, and improved mood.

What are the downsides?

Fasting is not recommend for children or pregnant women. Moreover, it may not be appropriate for people with a history of eating disorders. If you have diabetes or are taking glucose-lowering medications you must be monitored closely by a medical provider.

In general, before starting any new eating plan it is important to notify your medical providers. Seeing a nutritionist is a great place to start to help make better food choices and get overall healthy eating recommendations. If you are still struggling to lose weight, consider seeing an endocrinologist/obesity specialist.

Reshmi Srinath, M.D., is an assistant professor in the Department of Medicine, Division of Endocrinology, Diabetes and Bone Disease at The Mount Sinai Hospital, and director of the Sinai Weight and Metabolism Management Program.