For probably the first time in the history of diets — from the vinegar and biscuits ‘bamming’ of the Regency era to the modern paleo and keto diets — one diet type has got an overwhelmingly positive nod from nutritionists and doctors. They may disagree on the finer points of how one practises it, but experts across the panel largely agree that periodic fasting is good for the human mind and body, and positively impacts a large number of functions, from enhancing the diversity and health of the gut microbiome to increasing insulin efficiency in the body and kickstarting a sluggish metabolism.
And this is not alternative medicine mumbo-jumbo—animal studies and human clinical trials across the world have shown the mechanism of many of these actions. A 2020 review conducted by the US National Institute on Ageing and published in the New England Journal of Medicine says that “evidence from decades of animal and human research points to wide-ranging health benefits of intermittent fasting. Evidence is accumulating that eating in a 6-hour period and fasting for 18 hours can trigger a metabolic switch from glucose-based to ketone-based energy, with increased stress resistance, increased longevity, and a decreased incidence of diseases, including cancer and obesity,” say the authors of the paper.
Studies have shown that intermittent fasting (IF) can change the makeup of the gut microbiome, encouraging the growth of good bacteria like Akkermansia muciniphila associated with decreased intestinal inflammation and a healthier gut. Other studies on animal subjects have shown a link between IF and reduction of brain inflammation, ultimately slowing down the neuro-degenerative process that causes diseases like Alzheimer’s in humans.
With a diet that promises so many benefits—and is seemingly not that difficult, since people report benefits from simply following the circadian rhythm, eating their last meal at sunset and the first meal after sunrise—it may seem like anyone can do IF and become leaner and healthier. Is that necessarily true?
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Functional nutritionist and TEDx speaker Mugdha Pradhan, founder of ThriveFNC, a nutrition and wellness focused startup, makes an interesting point when she says that while IF helps us build a healthy relationship with food, it may be a rough start for those who use food as emotional support. “We humans have an intensely emotional relationship with food. Food grounds us, it makes us feel whole. We eat not just for sustenance but for many reasons...for taste, for social bonding, and sometimes because it fills some other need in us. Jumping into IF without fixing your relationship with food, without preparing your body and mind, is not a good idea,” says Pradhan. She suggests a period of stock-taking before starting IF—getting your health parameters checked, and making sure your mental health is on track, including being aware of your stress-eating patterns, because it can potentially lead to mood swings, cravings, and migraines, at least initially.
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In the long term, though, IF has been shown to be beneficial for mental health as well. The results of a study published in the Journal of Nutrition Health & Aging in 2020 found that after three months of IF, participants reported improved moods and decreased tension, anger, and confusion.
Lifestyle coach Luke Coutinho, founder of Luke Coutinho Holistic Healing Systems, says IF is probably not a good choice for the following groups of people: extremely weak and fragile individuals, pregnant and breastfeeding mothers, those who need to have multiple medications several times a day, highly diabetic individuals who need to eat every 2-3 hours, and those on water restrictions, such as those suffering from kidney disease. “Having said that, by far one of the most natural and safe methods of fasting is circadian rhythm fasting. It honours the circadian rhythm set by nature and encourages us to start and stop fasting according to that. A simple sunset to sunrise fasting which accounts for approximately 12 hours can be practiced by most individuals as that is how humans were always designed to eat,” says Coutinho.
“IF helps the gut recover, rejuvenate, re-inoculate and repair—what I call the 4 R’s. Eating constantly fatigues the digestive system and fasting gives it time to recuperate. In the initial few days you may have to deal with some acidity, but slowly acid production in the stomach goes down as the stomach lining gets used to the new eating schedule. Our bodies are very intuitive,” says nutritionist and gut health coach Payal Kothari, author of The Gut: The Story of Our Incredible Second Brain. “In some ways, IF is an ‘easy’ diet to do because you don’t have to count calories and obsess over what and how much you’re eating within your eating window. But that does not mean, as some people seem to believe, that you can eat ‘anything’ within the 8 hours if you’re doing a 16:8 fast (16 hours of fasting with an 8-hour eating window). You may see some initial weight loss if you do that but it will soon plateau,” says Kothari.
So that myth stands busted—while IF is a largely fuss-free diet and you don’t necessarily have to count calories and ‘macros’ or eat only high fat and high protein foods (or only nuts and foraged foods like your hunting-gathering ancestors), you can’t eat doughnuts and pizzas during your eating window and still hope to get the full benefits of IF. “Eat sensibly” during the eating window is what most nutritionists and doctors will advise—so more plant-based foods than animal protein, more whole grains with high fibre content, less sugar and fewer processed foods.
Some people report periods of dizziness and fatigue after breaking a longish fast, mainly because of blood rushing to the stomach and intestine to digest the food quickly, leading to lowered blood pressure. Is IF good for them? It is important to understand the correct way to break a fast, says Coutinho. “During fasting, our digestive system takes a back seat and the digestive fires are low, so it is necessary to ease into breaking your fast. Never rush into it by guzzling fruit juices or eating a plate of fruits. That is capable of overwhelming your body. Instead, slow down, drink some lemon water, eat dates or a banana after some time, and gradually eat a wholesome home-cooked balanced meal after 45 mins to an hour. This pattern will help wake up your digestive fires gently and the transition from fasting state to feeding state will be smooth.”
Nutritionists also note that even the 16:8 or 14:10 fasting patterns don’t have to suit you; your body may give you the same results with just 12 hours of fasting, so simply eating dinner early and fasting between 8 am and 8 pm can work wonders. But what about midnight cravings? “Brush your teeth and go to sleep,” says Pradhan.