Article from Lindsay Martin, MS, RDN, LDN | 

Intermittent Fasting: Does it help with weight loss? 

Intermittent fasting is a trendy way of eating these days, but many ask me: “Is it safe? Will it work for weight loss? How do I do it and what do I eat?”  Well don’t worry, I will answer all your questions and let you decide if it’s for you.

Intermittent fasting is an eating plan that switches between fasting and eating on a regular schedule. Research shows that intermittent fasting is a way to manage your weight and prevent or even reverse some forms of disease.

Many diets focus on what to eat, but intermittent fasting is all about when you eat. With intermittent fasting, you only eat during a specific time. Fasting for a certain number of hours each day or eating just one meal a couple days a week, can help your body burn fat. And scientific evidence points to some health benefits, as well.

Johns Hopkins neuroscientist Mark Mattson, has studied intermittent fasting for 25 years. He says that our bodies have evolved to be able to go without food for many hours, or even several days or longer. In prehistoric times, people were hunters and gatherers who evolved to survive and thrive for long periods without eating. They had to because it took a lot of time and energy to hunt and gather nuts, seeds and berries.

Even 50 some years ago, it was easier to maintain a healthy weight. There were no computers, and TV shows turned off at 11 p.m.; people stopped eating because they went to bed. Portion sizes were much smaller. More people worked and played outside and, in general, got more exercise. So what changed? Well now television, the internet and other entertainment are available 24/7 and distract us from getting exercise. We stay awake for longer hours to catch our favorite shows, play games and chat online. We’re sitting and snacking all day and most of the night. Those extra calories and inactivity can mean a higher risk of obesity, type 2 diabetes, heart disease and other diseases and illnesses. Scientific studies are showing that intermittent fasting may help reverse these trends.

So, how does intermittent fasting work?  There are many different ways to do intermittent fasting, but they are all based on choosing regular time periods to eat and fast. The most common regimen is 16:8; you eat only during an eight-hour period each day and fast for the remaining sixteen hours. Or you might choose to eat only one meal a day two days a week. There are many different intermittent fasting schedules and you have to see what will work for you and your lifestyle.

After hours without food, the body exhausts its sugar stores and starts burning fat.  Mattson refers to this as metabolic switching.

Intermittent fasting contrasts with the normal eating pattern for most Americans, who eat throughout their waking hours. If someone is eating three meals a day, plus snacks, and they’re not exercising, then every time they eat, they’re running on those calories and not burning their fat stores.  Intermittent fasting works by prolonging the period when your body has burned through the calories consumed during your last meal and begins burning fat.

Mattson’s research shows that it can take two to four weeks before the body becomes accustomed to intermittent fasting. You might feel hungry or cranky while you’re getting used to the new routine. But, he observes, research subjects who make it through the adjustment period tend to stick with the plan, because they notice they feel better.

What to eat while intermittent fasting?

During the times when you’re not eating, drink water and zero-calorie beverages such as black coffee and tea.  And during your eating periods, “eating normally” does not mean going crazy. You’re not likely to lose weight or get healthier if you pack your feeding times with high-calorie junk food, fast food and treats.  But what I like about intermittent fasting is that it allows for a range of different foods to be eaten and enjoyed. I suggest people to be mindful and take pleasure in eating wholesome, nutritious food and eating with others, sharing the mealtime experience adds satisfaction and supports good health.

Anyone that knows me well, knows I always suggest the Mediterranean diet as a good guide of what to eat, whether you’re trying intermittent fasting or not. You can hardly go wrong when you pick complex, unrefined carbohydrates such as whole grains, leafy greens, healthy fats and lean protein.

Intermittent Fasting Benefits

Research shows that the intermittent fasting periods do more than burn fat. When changes occur with this metabolic switch, it affects the body and brain.  One of Mattson’s studies published in the New England Journal of Medicine revealed data about a range of health benefits associated with the practice. These include a longer life, a leaner body and a sharper mind.

Many things happen during intermittent fasting that can protect organs against chronic diseases like type 2 diabetes, heart disease, age-related neurodegenerative disorders, even inflammatory bowel disease and many cancers.

So, is intermittent fasting safe?  Some people try intermittent fasting for weight loss or management, and others use the method to address chronic conditions such as irritable bowel syndrome, high cholesterol or arthritis. You should check with your primary care practitioner first. Some people should steer clear of trying intermittent fasting if you are under the age of 18, pregnant or breastfeeding, have diabetes or blood sugar problems, or those with a history of eating disorders. Also it’s important to speak with your primary care practitioner if you start experiencing unusual anxiety, headaches, nausea or other symptoms after you start intermittent fasting.

References: https://www.nejm.org/doi/full/10.1056/nejmra1905136