A healthy living blog from Marshfield Clinic Health System

5 tips for intermittent fasting

A woman eats a granola bar.

If you’re considering intermittent fasting, there’s a lot to take into account, such as how healthy it is and what type of fast may be right for you. Read these five tips.

It’s the most searched diet on the internet. More and more research is being published about its surprising health benefits. The trend of intermittent fasting, or abstaining from or reducing eating, drinking or both for a set time, continues to sweep the nation.

If you’re considering fasting, there’s a lot to take into account, such as how healthy it is and what type of fast may be right for you. Some introductory info on the diet is here.

Dr. Michael Larson, Marshfield Clinic Health System Clinical psychologist and expert in the psychology of weight management, shares how you can make sure your fasting is healthy, effective and fun.

It’s natural to have fear over a new diet

Larson noted that most of us have been told that we need to eat three meals a day and that breakfast is the most important meal, but actually, our bodies were made to fast.

“Our bodies are made to store fat and then use it for energy and nutrition at a later date,” said Larson. “Unfortunately, most of us never get around to using our fat. Fat is ‘perfect’ energy for our body.

Larson teaches in his employee and spouse psychology of weight management classes that there are really only two ways we gain access to our fat by controlling insulin, which is our primary fat storage chemical:

  • By limiting sugar and flour intake
  • Or by not eating and forcing our body to eat that fat – a concept he refers to as “dining in on your fat.”

“Current research suggests that it may be as important when we eat or don’t eat as it is what we eat,” said Larson. “Both appear to be important factors in terms of weight loss.”

Once the fear of not eating is overcome, Larson said that intermittent fasting has a variety of advantages.

  • It’s easy to follow due to no calorie-counting needed and is very cost-effective.
  • Early studies suggest a potential advantage for cancer prevention, dementia and Alzheimers.
  • Impact on insulin resistance and as a treatment for diabetes has also been noted.
  • The individual’s cognitive function improves.

“Our brain and body have several mechanisms that allow us to have better brain function the longer we don’t eat,” Larson said. “People and rats show better endurance when they eat one day and not the next than their counterparts who eat every day.”

Larson highlighted a New England Journal of Medicine study that covered this topic and can attest from his own personal experience. Fellow employees and their spouses who attend his class and fast have shared how they are feeling and improving cognitively while on the diet.

Because the concept of fasting and intermittent fasting are relatively new, Larson expects that studies over the next few years will show many other health benefits related to intermittent fasting when done safely.

Listen to your body

“I generally encourage people to limit sugar and flour during their eating window so it’s easier to go into the next fasting state,” Larson said. “The body is already living on its fat and gets used to burning fat – so avoiding sugar and flour can make it easier to transition into noneating windows.”

As for what type of window works best for fasting, it’s all about finding the plan that works best for you. Larson personally fasts for 22 hours each day, with a two-hour window where he enjoys all sorts of good foods. Other people use a 16 hour non-eating window and then will eat several meals within their 8 hour eating window.

“Intermittent fasting is not starvation,” Larson said. “It could also be called intermittent eating.”

Drink water, coffee and tea during fasting

“If you do extended fasting, we promote bone broth because it has minerals and nutrients,” Larson said. “It is a true fast when we limit ourselves to only water, coffee, tea or bone broth.”

The psychology behind weight loss

“We’re such emotional eaters,” Larson said. “From a psychological standpoint, when we have an emotion, we know we can change emotions in several ways.”

Larson gave the example of someone who may be lonely and grabs some ice cream to help distract from that loneliness.

“A second thing happens with this — when the sugar hits our system, the brain releases dopamine which is one of our feel good or reward chemicals. So over time, when loneliness occurs again, we know that we can change our emotional state by eating due to the distraction and dopamine release.”

So as focus turns to starting a new diet, attention also needs to be paid to managing emotions better. “There are so many things we can pair together about how our bodies can lose weight and how our brains are involved,” Larson said. “When all done the right way, it becomes much easier to lose weight, manage it and never gain it back.”

Some precautions to follow

Larson advised that caution is indicated when fasting is considered for certain groups. It is not currently recommend for children and requires medical supervision in those people with diabetes that are on medication or insulin.

Larson added that some individuals with diabetes have experienced benefits when fasting in a limited manner and one of the leading experts in fasting, Jason Fung, M.D., actually promotes closely monitored fasting for individuals with diabetes.


If you are looking to do intermittent fasting or would like to learn more, a good first step would be discussing it with your primary care provider or registered dietitian.


  1. Jul 22, 2021
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