Intermittent fasting: Can it really work for you?

Experts analyse the pros and cons of this eating plan and its impact on those with diabetes and heart disease

WHEN HE tried intermittent fasting (IF) for a couple of days, diabetes specialist Dr V Mohan found himself rolling in pain. “If you don’t eat for long durations, the hydrochloric acid remains in the digestive system, leading to severe gastritis. I knew this diet plan was not for me,” he says. However, some people swear by its transformative ability in building good health, particularly in weight management. One of Dr Mohan’s colleagues has been living on one meal for years now.

Like the varied impact on users, the results of clinical trials of time-restricted eating have been mixed. While short-term studies have demonstrated some benefits, a recent longterm study showed that such a diet plan could be associated with a 91 per cent increased risk of death due to cardiovascular diseases such as heart attacks and strokes. While each study has variable factors and flawed methodologies, the question is, can such diets work in the long-run?

What is intermittent fasting?

There is not one definition but it is an eating plan that switches between fasting and eating on a planned schedule at specific times. While most diets focus on what to eat, intermittent fasting is all about when you eat. This could involve having meals either in an eight or 10-hour window every day and fasting for the rest or eating for five days a week and fasting for two. The idea is to align the eating habits with the body’s sleep-wake circadian cycle and harmonise the body’s functioning with it.

For such a plan to work, one must also eat clean and count calories. “Intermittent fasting without calorie restriction is not useful. If you are consuming more calories in two meals than you would across four or five smaller meals, how will that help you in losingweight or controlling blood sugar levels ?” asks Dr Mohan.

Is intermittent fasting for everybody?

Other than symptoms of gastritis as experienced by Dr Mohan, many practitioners experience depression caused by food denial during fasting periods. “If this seems like an imposition, then intermittent fasting may not be for you. Having four or five smaller meals through the day may be more effective,” adds Dr Mohan.

Besides, you should be able to carry on with your normal day-to-day activities during the fasting periods effortlessly. As Mumbai-based diabetologist Dr Anil Bhoraskar says, “People should not feel tired or feel like lying down during the fasting window. Giddiness, lack of concentration and palpitations could indicate slowing of pulse rate or a drop in blood pressure.” In other words, it is best to take advice from your doctor and dietician before any change you make in your eating plan and factor in your body conditions.

Eating plans for healthy people

Dr Justin Paul, professor at the Institute of Cardiology at Madras Medical College, suggests a graded approach for those starting out. “In India, the eating window spans over 14 hours, from the time we wake up and have our morning tea or coffee to the time we eat dinner. Begin by reducing the eating window to 12 and then 10 hours. Anything less than that, I am not sure about. When we align our eating period with our circadian rhythm, our body works more efficiently.”

It is the overeating that has Dr Mohan concerned. “One of the principles of intermittent fasting is not eating your breakfast, lunch and dinner at the designated timings if you are not hungry. And that is a good principle. If you are not hungry, it means there is still undigested food in your gastro-intestinal tract and a signal that you should not overeat. Skip a meal if you have had a heavy protein-rich breakfast. In the early stages of evolution, humans never ate this much. Meal timings are a very recent phenomenon in our evolutionary history,” he says.

If your blood sugar, cholesterol, blood pressure and weight parameters are within range, track your protein intake to ensure a good body composition. Experts suggest cutting the amount of carbohydrates, particularly the refined kind, as a typical Indian diet relies heavily on them.

Should people with diabetes and hypertension take up IF?

With diabetes and hypertension being silent diseases — where the symptoms are not obvious and immediate — it is essential for dieters to get screened for these conditions if they are planning a significantly different eating pattern. Studies have shown that 57 per cent of people with Type-2 diabetes and nearly 73 per cent with hypertension are unaware of their diagnosis in India.

Dr Bhoraskar rules out fasting of any kind for those with diabetes and on medication or insulin. “Fasting for long periods can lead to a drop in blood sugar levels, which can sometimes be fatal for this group,” he says. Dr

Mohan, on the other hand, says those with Type-2 diabetes may be able to do intermittent fasting for shorter durations but under strict monitoring. “They have to adjust medicines accordingly. For example, if they have to take a pill in the morning with food, it may be deferred. However, it is difficult for people with Type-1 diabetes, who need to take insulin three or four times a day. They will have the risk of hypoglycaemia or low blood sugar levels later in the day,” says Dr Mohan.

IF vs cardiovascular disease

Experts say that with the latest data showing at least some indication of increased cardiovascular risk — and it is just an indication because the new data set hasn’t been peer reviewed and is observational — the high-risk group should stick to tried and tested calorie restricted diets.

Dr Paul says that some fasting is good as it starts restorative processes in the body.

“When you eat as per your circadian rhythm, the body works better. When you give it rest, the body starts its restorative processes. So, time restriction is good. But how much time restriction is the question,” he adds.

Dr Bhoraskar explains how fasting for long durations can affect heart health. “The body produces counter-regulatory hormones such as catecholamine, adrenaline and noradrenaline. These increase the pulse rate and blood pressure, which can eventually damage the heart, especially in people who already have bad coronary arteries,” he says. Those on medicines for hypertension and heart diseases may also be prone to imbalance in sodium, potassium and other minerals in the long-run.

So far, there is no data to justify improvement in cardiovascular markers. A Cochrane review of 18 studies concluded, “We are uncertain about the effects of intermittent fasting on clinical events such as mortality, myocardial infarction and heart failure due to lack of data for these outcomes.”

A 2019 study in the journal says while IF can limit many risk factors for heart diseases such as obesity, diabetes and hypertension, “it remains questionable if these benefits are solely due to weight loss or nonweight loss mechanisms.”

The same study warned against fasting for people with hormonal imbalances, pregnant and breastfeeding women, diabetics, those with eating disorders and those who are underweight. In the end, a diet routine should work for you and not be another fad to follow.

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