Feasting and Fasting: Is It Safe?

Nov. 24, 2020

As we embark on the 2020 holiday season amid the tumultuous times of the COVID-19 pandemic, “intermittent fasting” for weight loss or weight maintenance – especially during the holidays – has been a topic of conversation.

Intermittent fasting - time restricted eating

In a normal world, the holidays can often involve elevated stress levels related to family dynamics, loneliness, weight gain and work demands. This year, add a global pandemic into the mix. These stressors can often lead to overeating and binge eating during the holidays.

With this in mind, the question remains: Is an intermittent fasting diet schedule safe and effective?

Malti Vij, MD, UC Health primary care physician and medical weight loss expert, is board certified in obesity medicine. She is knowledgeable about this diet concept, which she calls “feasting and fasting.”

What is intermittent fasting?

“Intermittent fasting means periodic intervals of abstaining from food, mixed with routine eating,” says Dr. Vij. “It can take different forms including periodic fasting, intermittent calorie restriction or alternating fasting schedules, but basically it’s abstaining from food on a periodic basis.”

Clear physiology exists behind this diet approach. “We all go through normal fasting every night when we sleep, for those eight to 12 hours,” states Dr. Vij. “Everyone is thrown into this mode of fasting on a nightly basis.” In addition, insulin is the key hormone behind fasting. She clarified, “Whenever we eat, the body releases a gush of insulin to help digest food, which will be used for energy deployment. The rest of the food ingested is stored.”

With a surge of insulin comes a problem – it is also a fat-storing hormone. “Our bodies try to make us fatter by conserving or storing it as energy,” states Dr. Vij. “With fasting, there is no surge of insulin, therefore food is not stored. In other words, the body is switching from food storage to food utilization – it’s trying to break down the fat/glucose which is already stored. This is the concept behind weight loss.”

In the 1970s, there were no concerns about eating five to six meals a day, Dr. Vij explains. “People were eating three meals a day, and we were not having any issues with obesity at that time. Today, there are myths and misconceptions about how many times per day we should be eating.”

Eating Should be Driven by Hunger

The general rule is that eating should be driven by hunger – and we should all avoid mindless eating or stress eating that packs on the pounds.

Also, what you eat matters. If you are consuming candy bars, chocolates or other unhealthy foods, they do not help your cause. “Feasting and fasting should be individualized,” says Dr. Vij. She reminds us again that we should feel hungry and not allow emotion to push us to grab the easiest or first food item available. Also, do not let stress tempt you to eat more when you aren’t really hungry.

Are there different types of intermittent fasting schedules?

While a standard, clear regimen does not really exist, Dr. Vij says that various fasting options are available.  

A time-restricted schedule means that a person fasts for several hours at a time, up to eight, 16, 20 or even 24 hours. Some people observe a fast for 24 hours every other day which is called alternate-day fasting. And some people do what is called a ‘5:2’ fast where you eat for five days and then fast for two days.

Is intermittent fasting proven to be safe?

Is there proof that fasting does not jeopardize a person’s health status? Are there evidence-based studies or clinical trials that support the notion that fasting can help with weight loss or maintenance?

“Currently, we lack robust studies and evidence-based research about fasting,” Dr. Vij says. “There are some studies out there, but the challenge is that they do not have enough human research objects (participants). We need more studies to confirm that it works or does not work. It has, however, been seen to be working in animal studies which is good.”

In fact, animal studies have been going on for decades. Findings have shown that when feeding rodents every other day, they not only remain lean, but develop fewer aging-related diseases and live 30-40 percent longer. In a 2019 review article in the New England Journal of Medicine, the findings of many animal studies were summarized, stating that in rodents and to some degree in monkeys, intermittent fasting is a “fountain of youth,” lowering body weight, blood pressure and cholesterol levels, improving glucose control, reducing system inflammation, maintaining brain health and boosting endurance and coordination.

Dr. Vij adds, “More recent articles state that all of these studies of random objects tell us that intermittent fasting is almost as effective as general calorie-restriction diets, if not more, in terms of weight loss and in terms of cardiometabolic health.” Medical experts describe cardiometabolic disease as a spectrum of conditions that begin with insulin resistance, then progress to metabolic syndrome, pre-diabetes, and finally to more serious conditions including cardiovascular disease and type 2 diabetes.

While more research is needed, Dr. Vij states that it is known intermittent fasting has been shown to have anti-inflammatory, anti-aging and metabolic health effects, and can promote healthy gut microbiomes. This is especially true for people who have diabetes, decreased glucose tolerance and those who are in the habit of snacking, or the “emotional eaters.” It can help break unhealthy food habits, meaning we don’t have to eat just because it’s there.

The bottom line is that we need a few more studies and additional research. In the meantime, Dr. Vij says intermittent fasting can be a viable option for some people.

“Fasting can be done safely, but it’s not for everybody. Those who have underlying health conditions such as diabetes, hypertension, low blood pressure, etc., should check with their doctor to make the right decision for them. Further, their doctor may need to adjust some medications before embarking on such a regimen.”

Others who have normal physiological conditions, such as pregnancy or malnourishment, are not advised to follow a fasting diet, according to Dr. Vij. She adds, “However, most of the time, it can work for most people, and they just need to work with their doctor to make modifications to fit their individual health status.”

Feasting and Fasting This Holiday Season

What about those people who are thinking, “I’ll just pig out on Thanksgiving and then do a fast afterward?”

According to Dr. Vij, it can be a viable approach, but with the proper mindset. “Of course, you want to be cognizant of your food choices on the days when feasting, including Thanksgiving and on other holidays this time of year. It cannot be a day when you are eating all carb foods. These poor choices will not help as much,” she states.

“Fasting does help with calorie restriction. If you have no health issues and choose to eat a normal Thanksgiving meal and then fast the following day, it is likely OK to do so.” She adds, during fasting, you must be careful about certain things, including drinking enough water and resisting possible cravings. “You should be ready to feel hungry while you are fasting, and it’s important to be patient with that.”

When a fast has ended, we should eat protein-rich foods and healthy fats, such as nuts and celery with hummus or peanut butter, while avoiding refined carbs and sugary snacks. Also, chewing your food properly is helpful with digestion.

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