Is Intermittent Fasting Healthy?

'Any dietary approach is incomplete without physical exercise.'
'Application of calorie restriction/intermittent fasting alone would lead to a decrease in muscle mass, and possibly bone mass too.'

Recent research by the American Heart Association on intermittent fasting has created confusion. While intermittent fasting is seen as an effective way to lose weight, the American Heart Association warned that the eight-hour time-restricted eating is linked to a 91% higher risk of cardiovascular death.

What does this mean for India which is already the diabetes capital of the world and ranked third in obesity after the US and China?

Distinguished diabetologist Dr Anoop Misra, who is chairman of the Fortis-CDOC Centre of Excellence for Diabetes, Metabolic Diseases and Endocrinology, New Delhi, and President, Diabetes Foundation (India), tells Rediff.com Contributor Shobha John that he would recommend intermittent fasting only to those with mild diabetes and obesity, never to diabetics.

What are your views regarding the American Heart Association research that eating during the 8-hour window when doing intermittent fasting was associated with a 91% increase in risk of cardiovascular death?

Clearly, this research has gained worldwide attention and led to a re-examination of intermittent fasting and overall health.

The study has been published as an abstract, and complete details are not available. Some shortcomings have been noted, the most notable being that data was collected with the help of a questionnaire, which could lead to misleading results.

On the other hand, it is based on results from a long-term study. So, in my opinion, the jury is still out.

Once the paper is published, we shall know more about it. Until that time, one should be cautious when applying intermittent fasting to individuals who have heightened heart risk or heart disease.

What is intermittent fasting and what are its advantages?

Intermittent fasting is an eating pattern which cycles between periods of fasting and eating. It doesn't specify which foods you should eat, but rather when you should eat them.

There are several methods of intermittent fasting, but the most common is fasting between 8 and 16 hours/day with no food consumed. Fasting could also be done for 24 hours every few days.

It has been shown to decrease weight and benefit metabolic parameters. Perhaps the most important point for its popularity is its simplicity as no detailed or continuous coaching or supervision is needed.

Can it be effective only when fasting for 16 hours and eating during an eight-hour window? What about a 12:12 hour eating/fasting window?

Intermittent fasting can still be effective with a 12-hour fasting window and a 12-hour eating window.

While it may not provide the same degree of fasting benefits as more extended fasting windows, it can still offer some advantages, particularly for those who find longer fasting periods challenging or unsuitable for their lifestyle.

The popularity of intermittent fasting as compared to other diets is that there is no dietary restriction. Can this lead to either a deficit or an excess in the number of calories needed per day?

To me, this approach seems lopsided. It could lead to disorderly eating, with no restrictions on the type of food consumed during the eating window. This may also result in uneven calorie intake.

For example, a person may take excess fats or carbs than required and this could be harmful. The metabolism following such eating could become damaging.

Can intermittent fasting alone be used for weight management or would you advise some form of exercise too?

Any dietary approach is incomplete without physical exercise. Application of calorie restriction/intermittent fasting alone would lead to a decrease in muscle mass, and possibly bone mass too.

It is very important to maintain these during dietary intervention.

Would you advise diabetics to follow intermittent fasting? After all, it reduces obesity by burning fat and aids in diabetic management.

I would never recommend this approach to my patients with diabetes, except perhaps for those who have mild diabetes and are obese, seeking weight loss.

My strategy involves calorie restriction while ensuring a balanced diet from all perspectives, delivered in a timely manner for individuals with diabetes.

This will prevent fluctuations in blood sugar levels and effectively manage weight loss. This works beautifully in most patients.

Would you also subscribe to the view that one should finish dinner by 7 pm?

I do not subscribe to this view since the subsequent window without food extends to 12 hours, akin to intermittent fasting.

During this period, people with diabetes on drugs and/or insulin may have dangerously low sugars. Those eating early dinners should take a bedtime snack.

Which diet, in your view, is the best?

The Mediterranean diet is good as it has been scientifically proven to be beneficial for metabolism in the long term. However, it is often difficult to achieve the same components in an Indianised manner.

Ayurveda says that the time between major meals of the day should be more than three hours and never exceed six. Do you believe in this?

According to the general approach in patients with diabetes, the time interval between major meals should NOT exceed more than 3-4 hours, especially when they are on multiple drugs and/or insulin.

This rule does not apply to those without diabetes.

Most Indians have diabetes and heart disease at least a decade earlier than other populations. Why is this? It can't only be a genetic disposition.

If there is any genetic predisposition, we haven't found it as yet, but debate and research are going on.

More likely, metabolic maladaptation to the increased availability of food in the background of centuries of calorie deprivation may play a role.

It means two major issues -- first, the body is tuned to preserve calories in the form of fat, which is accumulated primarily in the abdomen. This abdominal fat releases harmful substances.

Second, the body does not know how to metabolise excess sugar effectively in the face of increased calorie intake. The consequences are many -- diabetes, high cholesterol, fatty liver, heart disease, cancers, infertility, etc.

In addition, there was news recently of advanced-stage trials for at least seven new drugs for weight loss in India. How effective are weight loss drugs and would you advise them to your patients?

Lifestyle changes are always the first answer. These are the only answer if we need to decrease diabetes or obesity in the whole population.

However, for a particular individual who continues to gain weight despite lifestyle measures, these drugs are excellent choices.

There are, however, two concerns -- a few adverse effects and these drugs are costly.

Perhaps these drugs are a suitable answer to those who need bariatric surgery.

Bariatric surgery remains the first choice for very obese patients. It is proven to produce a high magnitude of weight loss and is known to reverse diabetes and other conditions such as fatty liver and obstructive sleep apnea.

If a person does not agree to surgery, these drugs provide an alternative solution.

Many obese people now are opting for these weight loss drugs instead of bariatric surgery.

IMAGE: Dr Anoop Misra. Photograph: Kind courtesy Dr Anoop Misra

The drug Semaglutide has been seen by some as a wonder drug as it helps in diabetes management, weight loss and brings down blood pressure and cholesterol. How does it work and are there any side effects?

Semaglutide is no wonder drug, but has good weight loss potential. Other drugs available in the US or under development can lead to even greater weight loss.

Semaglutide and other similar drugs work by decreasing appetite and decreasing muscle movement of the intestine to achieve weight loss. But weight loss is not assured in every person, and some may respond poorly.

Do you foresee fierce competition among these companies in the years to come? After all, India has some 80 million individuals who are obese.

It is going to be a war of the weight loss drugs during the battle of the bulge!

Also, will injectables for weight loss need to be regulated to prevent misuse. Who all should use them?

A good physician should be able to choose the right person for these drugs.

They should not be used in those with a family history of thyroid cancer, a history of pancreatitis and severe intestinal disease.

After initiation, nausea or vomiting may be severe in some people, but eventually will go away.

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Feature Presentation: Ashish Narsale/Rediff.com