intermittent fasting benefits risks weight loss
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Have you been thinking about intermittent fasting because your Facebook feed is flooded with posts about it? Or do all your friends and family keep listing the benefits of this new awesome style of dieting? You are being driven towards it, aren’t you? Before you switch to this new lifestyle, take a step back and ask yourself, “Is it really worthwhile?”

Don’t go too far looking for answers. Intermittent fasting has been adopted from age-old religious and spiritual fasting patterns. Scientists replicated fast-like conditions for mice and saw some benefits in terms of weight loss. This gave rise to the idea of intermittent fasting. (1)

So, the concept of intermittent fasting is to alternate between phases of famine and feasting. In the famine phase, you fast for 24 hours at least once a week, or you may even go up to 4 non-consecutive days of fasting in a week. In the feasting phase, you eat as you like, to your heart’s content. (2) How tempting does that sound? You can control your urges for a day or two in the week and eat your heart out for the rest of the week!

If we were to list the benefits of intermittent fasting, the words ‘insulin sensitivity’ would be at the top of that list. Research says fasting makes your body more sensitive to insulin. Insulin is the hormone that helps the cells of your body to take up glucose from the blood. This means your body absorbs glucose more effectively after fasting, thus reducing the blood glucose levels and reducing the risk of diabetes and other age-related disorders.

It has been shown to have beneficial effects on mental health too. Woah! Could it get any better? Some scientific papers even claim that it prevents brain function decline and can reduce the risk of heart-related disorders as well! (3,4)

However, is it as easy as it sounds? Let’s clear some of the myths about intermittent fasting:

1. Not all that jazz:

A recent study from April 2019 noted that intermittent fasting does not bestow many benefits when one is eating a high-fat diet on feast days. A regular diet is recommended for any prominent weight loss. So, it’s not like you can indulge in ice creams and mouth-watering jalebis on your feast days. (5)

2. Bingeing is not the key:

Another study from December 2018 showed that there could be no weight loss achieved if you were to compensate for the food deprivation of the famine day by eating all those calories on the feast day. Basically, it is of no use starving yourself if you plan to eat all of that the very next day. (6)

3. Humans or rats?:

Most studies about the beneficial effects of intermittent fasting have been performed on mice and may sometimes not show replicable results in humans. Recent studies from 2018 and 2019 come to this conclusion by the end of the study.

So, err…should you be following intermittent fasting at all? (2,6)

4. Go big or go home:

In one of the detailed reviews published at the beginning of 2019, researchers said that fasting should continue for at least 16 hours for you to see any weight loss. Jumping from regular eating patterns to strict fasting can be really harmful to the body and can get extremely difficult. The review also emphasised the fact that better study designs as well as including diverse groups of people are needed to see the real effects of fasting on individuals of different ethnicities and metabolisms. (7)

5. Exhaustion Incoming:

Another evidence comes from the book “Advanced Nutrition and Dietetics in Obesity” which was published in 2018; it has contributions from scientists across the globe. It states the importance of consuming a balanced meal on feast days and stresses on the fact that the greater the weight loss, the greater will be the fatigue experienced by you. In addition to the studies mentioned earlier, this book also points out the missing parallelism between human and rat studies. (8)

6. Harvard said it first:

The Harvard School of Public Health recently published an article comparing intermittent fasting and other methods of weight loss. The article mentions that it gets extremely difficult for people to continue intermittent fasting in the long term and instead leads to increased cholesterol levels at the end of a year. (9)

We understand weight loss can be daunting, and we all want a quick fix. Intermittent fasting does provide that quick fix, but it still leaves many questions unanswered. Questions like “Will I gain all the weight I lost after I go back to my lifestyle?” or “Which foods can I really eat on my feast days?” or even “Can I eat at any time in those 24 hours?”

Other potential doubts that arise from these studies are as follows:

  1. What are the long-term effects?
  2. Does everyone’s body respond in the same way?
  3. Are there any gender-based differences in the diet plans?
  4. What about people at risk for chronic conditions like diabetes and heart disorders? (9)

There are many loose ends that need attention and clarity. Let science do the work. Till then, continue to keep your motivation high and work towards your fitness goals with your nutritionist or doctor. And, most importantly, keep an eye out for the *conditions apply* tag before you venture into this new life-transforming journey!

References:

  1. Persynaki A, Karras S, Pichard C. Unraveling the metabolic health benefits of fasting related to beliefs of religion: A narrative review. Nutrition. 2017;35:14-20. doi:10.1016/j.nut.2016.10.005. 
  2. Hutchison AT, Liu B, Wood RE, Vincent AD, Thompson CH, O’Callaghan NJ, et al. Effects of intermittent versus continuous energy intakes on insulin sensitivity and metabolic risk in women with overweight. Obesity. 2019;27(1):50-58. doi:10.1002/oby.22345.
  3. Grajower MM, Horne BD. Clinical management of intermittent fasting in patients with diabetes mellitus. Nutrients. 2019;11:873. doi:10.3390/nu11040873.
  4. Sharma A, Kaur T, Singh H, Kaur G. Intermittent fasting-dietary restriction as a biological hormetin for health benefits. In: Rattan S, Kyriazis M, editors. The Science of Hormesis in Health and Longevity. 1st ed. Chennai. Elsevier Inc; 2019. p.99-102.
  5. Niepoetter P, Colley Z, Viernow C, Allen A, Gopalan C. The efficacy of intermittent fasting in weight reduction in non-obese and obese rats. Presented at: Experimental Biology 2019 meeting; Abstract 336.1. The FASEB Journal. 2019. doi:abs/10.1096/fasebj.2019.33.
  6. Liu B, Page AJ, Hutchison AT, Wittert GA, Heilbronn LK. Intermittent fasting increases energy expenditure and promotes adipose tissue browning in mice. Nutrition. 2019 Oct;66:38-43. Available from: https://doi.org/10.1016/j.nut.2019.03.015.
  7. Templeman I, Gonzalez JT, Thompson D, Betts JA. The role of intermittent fasting and meal timing in weight management and metabolic health. Proc Nutr Soc. 2019 Apr 26:1-12. doi:10.1017/S0029665119000636.
  8. Hart K. Fad diets and fasting for weight loss in obesity. In: Hankey C, Whelan K, editors. Advanced nutrition and dietetics in obesity. 1st ed. Wiley-Blackwell; 2018; Chapter 4.6,p.177-181.
  9. Harvard T.H. Chan. Diet Review: Intermittent Fasting for Weight Loss [Internet]. [cited 2019 Jun 12]. Available at: https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/intermittent-fasting/.

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