When it comes to losing weight, people often want understand the best method to melted excess pounds – and also there"s no shortage of fad diets or fitness crazes claiming to have actually the "secret" come fat loss.

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One theory even suggests that working out at about 60 percent of her maximum heart price will carry our bodies into a so-called "fat burning zone", optimal for shedding weight.

But go this "fat burn zone" also exist?

First, it"s necessary to know a little about our metabolism. Even if we were come sit in ~ our desk all day, our body still needs "fuel" to meet energy demands. This energy originates from carbohydrates, proteins, fats and also phosphates.

However, the price at i m sorry we usage them, and also how lot we have available, varies between people. It depends on a variety of factors, such together dietary intake, age, sex and also how tough or regularly we exercise.

Generally, exercising at reduced intensities – such as sustained walking or light jogging – doesn"t need as much effort by ours muscles as sprinting, for example. This method the amount of power needed by the human body is lower, so power supply predominantly originates from fats.

But as exercise intensity increases, fat can"t it is in metabolised fast enough to meet increased energy demand. For this reason the body will use carbohydrates, together these have the right to be metabolised more rapidly. This method there is indeed an practice intensity whereby fat is the predominant energy source.


At the lower end of this spectrum is our relaxing state. Here, the number of calories our body requirements to duty is considerably low, therefore the body generally metabolises fat to usage for energy.

This method the potential "zone" because that metabolising fat is in between the rested state and the level of exercise intensity wherein carbohydrates become the leading energy resource (in regards to percent donation to energy demand).

But this is a broad range, which lies in between a resting heart rate of around 70 beats per minute to around 160 beats per minute throughout moderate initiative exercise (such together cycling in ~ a continuous speed wherein holding a conversation becomes challenging), where the crossover from making use of fat to carbohydrate for power occurs.

The problem with such a broad zone is that the person working out wouldn"t necessarily be optimising their ability to metabolise fat, since as the exercise intensity boosts there"s a gradual adjust in the balance of fat and also carbohydrates her body supplies for energy.

Fat burn zone

So how deserve to we recognize at which allude our body will switch from making use of fat to various other fuels because that energy? One technique researchers take it is assessing exactly how much fat is being supplied for energy during different exercise intensities.

By measuring just how much air a human being expels throughout an practice test which gets increasingly harder, physiologists have actually been may be to calculation the family member contributions that fat and also carbohydrates to meet the exercise demand at different intensities.


The highest possible amount that fat burned is dubbed the "maximal fat oxidation rate" (or MFO), and also the soot this occurs at is termed "FATmax".

Since this technique was an initial used by researchers, researches have presented that together the strongness rises from about 40-70 percent that a person"s VO₂ max – i m sorry is the maximum lot of oxygen a person can use during exercise – there"s rise in the rate of carbohydrates and fats being used. The price of fat being burned starts to decline at higher intensities as the body needs energy an ext rapidly.

The so-called "fat burning zone" has been presented to occur everywhere between around 50-72 percent that a person"s VO₂ max. However, the capacity to burn fat is also based top top genetics, with studies showing that this fat burning zone is most likely to be reduced in overweight or obese people – around 24-46 percent of your VO₂ max – and greater in endurance athletes.

Another allude to consider is how much fat we actually burn throughout exercise (if us express that in grams every minute). The prize is: surprisingly little. Even in research studies with athletes, in ~ FATmax, entrants only shed on mean a mere 0.5 grams of fat every minute. This would equate to roughly 30 grams of fat per hour.

In the median person, this shows up to be also lower, ranging in between 0.1 and also 0.4 grams of fat every minute. To put it in perspective, one lb of fat weighs roughly 454 grams. So, though training in this fat burning zone will assist with fat loss, this can also assist explain why the takes some human being longer to shed fat through exercise.

But over there is evidence that following details diets (such together intermittent fasting or a ketogenic, high fat diet) and longer exercise can increase the actual quantity of fat we burn.

Perhaps it"s time to no longer think about "burning fat" to have a "zone", however rather an individualised "sweet spot" which can be offered to optimise our exercise regimes to lose weight.

Regular physical task around this "sweet spot" (which frequently occurs in ~ a short to moderate emotion of effort, for example 30-60 percent of your maximal effort, or a regarded exertion level of one to four out of ten) will certainly likely boost our body"s performance in making use of fat for energy – and translate to a lower in its entirety body fat percentage.

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Justin Roberts, primary Lecturer, Anglia Ruskin University; Ash Willmott, Lecturer in Sport and Exercise Science, Anglia Ruskin University, and Dan Gordon, primary Lecturer Sport and Exercise Sciences, Anglia Ruskin University.

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This write-up is republished native The Conversation under a an imaginative Commons license. Review the initial article.