Thermogenesis: How this scientific buzzword will help you maintain weight loss

By Kimberly Gillan|

Revving up your internal thermostat could be the key to helping you lose weight and keep it off


Thermogenesis is one of the latest hot topics in obesity research and may sound very high-tech, but it's basically a fancy term for the generation of heat in your body.

Scientists are increasingly discovering that if you can activate thermogenesis in the right way, it can help you keep your body slim — basically the more you can fire up heat in your body, the more calories you'll burn.  

Now excuse us while we get a bit biology teacher on you — but it will be worth it once you realise how cool this bodily function is.

There are a few different types of thermogenesis. There is basal or resting thermogenesis, which is also known as your resting metabolic rate or resting energy expenditure. This refers to how many kilojoules your body burns to just keep you alive.

"You can change your resting energy expenditure by increasing your lean body mass — such as muscle mass — through strength training exercises, because lean body mass is the most important determinant of your resting energy expenditure," Associate Professor Amanda Salis, senior research fellow at the University of Sydney's Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, told ninemsn Coach.

So basically if you have bigger muscles then your body will burn more kilojoules when you're sitting around. So get squatting.

Then there's food-induced thermogenesis, which you'd be familiar with as that hot feeling you get after having a big meal — pleasant in winter but a bit sweaty and gross in summer (and helps to explain why we tend to prefer lighter meals when the mercury is high).

"When you eat something your energy expenditure speeds up because of digestive processes and assimilating the food into your body," Salis says.

"But we don't really focus on that sort of thermogenesis for weight management because, yes, if you eat lots you will increase your body's thermogenesis, but the fact you've eaten more kilojoules can counteract the beneficial effect."

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Then, of course, there's exercise-induced thermogenesis, which refers to the heat our bodies produce when we do a big workout, and is well-known as an excellent path to a slim body.

But perhaps the most interesting type of all is adaptive thermogenesis, which is the one scientists are honing in on in the hope of using it to help people maintain weight loss.

Adaptive thermogenesis refers to a slow-down of our metabolism or energy expenditure when we're eating less food. It explains why you often have great results at the start of a weight-loss diet, but then you often hit a plateau or the weight starts creeping back on.

"When you don't eat enough, you can go into what I call a 'famine reaction'," Salis explains.

"Adaptive thermogenesis is part of this famine reaction. Your body sees potential starvation and lowers your energy expenditure to help protect you. If you remain energy restricted, that famine reaction subsists."

While scientists are trying to hone in on some drugs that will stop adaptive thermogenesis from reducing your energy expenditure, for now, Salis says you may be able to help counteract it by taking diet "breaks" 

"Besides physical activity — including some strength training — the best thing you can do to keep your energy expenditure maximised is to make sure you are eating enough," Salis says.

"You don't want to eat too much but you don't want to walk around in a state of constant restriction, because this causes the process of adaptive thermogenesis to reduce your energy expenditure, or the number of kilojoules your body burns."

Forget the marketing hype

Some supplements claim to have "thermogenic properties" and there are rumours that foods like green tea and chilli can boost thermogenesis. 

But Salis says the science is definitely not clear and she cautions against falling for loose marketing claims.

"Although there are some foods that have been shown to increase energy expenditure/thermogenesis/metabolic rate, there's no strong evidence that they will give you a benefit in terms of weight management," Salis says.

"If you like chilli or caffeine, that's all good. But in terms of weight management, the effects are small and they can be easily washed out or over-run by other effects that are more powerful."

The take-home thermogenesis message

So for now, the best things you can do to help thermogenesis work in your favour is consistent with most other health messages — be active, including building muscle through strength training, and eat lots of healthy foods.

"In future, weight loss pharmaceuticals might be able to target adaptive thermogenesis to help people avoid weight loss plateaus," Salis says.

"We also know that bariatric surgery is effective in part because it changes adaptive thermogenesis, so if we could find out how it does that, then maybe we could use that knowledge and prevent that weight loss-induced reduction in energy expenditure using a less invasive procedure."

Associate Professor Amanda Salis and her team are currently seeking people living in the Sydney metropolitan area for clinical weight loss trials investigating thermogenesis. For more information, please register your interest here, or email Amanda's team on For information about other clinical trials around Australia, please click here.
