Science vs. Metabolism Myths

Science vs. Metabolism Myths
Join the conversation


A “fast metabolism”; the dieters dream and the hard gainers worst enemy. While most people believe that your metabolism is simply the process of how quickly you burn calories or stored fat within a given timeframe – it’s actually a lot more complex than that. If you’ve ever found yourself stuck in a diet rut, stick around because science is going head-to-head with some metabolism myths and trust me on this – science is a badass.

Your metabolism is defined as the sum of all of the chemical reactions that occur in your body in order to sustain life. These include such things as cell repair, growth and even death. A caloric deficit and the types of reactions that occur dictate whether or not you will use glucose (from carbohydrates), muscle or stored fat as an energy source. The speed of these reactions don’t have much of an impact on fat loss.

Although your metabolism governs much more than just weight loss, most myths and misconceptions regarding it refer to its fat burning abilities, so for the sake of simplicity we’ll stick to that scenario. It’s worth remembering though that the metabolism is complex and it’s not exactly something that can be “sped up” by eating every two hours or consuming copious amounts of caffeine.

So I’ve rounded up some of the most commonly believed myths about your metabolism and examined the truth (if any) behind them. No need to waste your time with funky teas and fad diets (don’t get me started on the “Baby Food Diet”!) because science has these myths well and truly busted.


This myth stems from the idea that your metabolism “goes to sleep” during the night and that breakfast “wakes it up” again, jump-starting the calorie burning processes. Your metabolism consists of all chemical reactions in your body, such as maintaining ideal body temperature and cell repair, which don’t just call it a day once you’ve hit the pillow. Sure, breakfast is great for giving you energy for the day (as well as preventing excessive snacking!) but skipping it is not going to have any significant effect on your metabolism or weight loss efforts.


This is ‘broscience’ in all of its glory! The idea behind this one is that for everything we eat, we burn about 10-30% of those calories just by digesting it. This is called the thermic effect of food and it sounds like it could work to our advantage but if you do the maths – it makes no difference.

Say you eat 3,600 calories a day and 10% of those calories are used during the process of digestion – that’s 360 calories total. Whether or not you burn those in one meal or in six meals it makes no difference as 10% of 600 calories six times a day is also 360 calories! Weight loss is all about a caloric deficit (consuming more calories than you expend) so don’t be worried if you go two hours without a snack – your body won’t shut down.

It’s worth mentioning that although eating more often doesn’t “speed up” the metabolism – going long periods (12+ hours) without food can push the body into conservation mode which can inhibit energy expenditure to some degree. Fasting can be a great way for people to “save” calories for a later time – just don’t overdo it and it isn’t something to be recommended to do on an ongoing basis!


This one causes so many people to burn their mouths off at dinner time but it’s all just hyped up a bit. This myth comes from the fact that our body does see an increase in thermogenesis (the production of heat) when we ingest eat certain foods such as chillis, caffeine and some others. An increase in thermogenesis will technically cause you to burn more calories – but this effect is short lived (ca. 30minutes) and has little to no effect in weight loss.


Am I the only one who thinks this one is absolutely ridiculous? I hope not! Juice “cleansers” and other “detoxes” do little else but rid the body of important nutrients that cannot be found in the fruits, vegetables or magical tea leaves used in the ‘cleansing’ process.

These cleansers often leave people feeling energised (usually from the high sugar content of fruit juices) for the first day or so, until the body becomes starved and goes into energy saving mode. The body is incredibly sophisticated and knows how to keep itself clean. Don’t try and do it yourself with some crazy concoction of tea leaves and vegetable stems!


This is actually technically true – but there is something you can do about it. Amongst all of the myths about speeding up your metabolism, there is one thing you can do to keep it firing as much as possible. Muscle tissue is metabolically very active – it takes more energy to sustain it than fat tissue. The more muscle you have, the more calories you will require to maintain your weight.

Sarcopenia – the progressive loss of muscle mass with increasing age – indirectly slows down the metabolism by decreasing the amount of metabolically (very) active muscle tissue. The cause of this phenomena is still unknown but you can delay and reduce its progression by consuming adequate amounts of protein (2g/kg bodyweight) and resistance training.


At the end of the day, the easiest thing you can do to keep your metabolism working as efficiently as possible is to treat your body well by supplying it with adequate nutrients (both macro and micro!), exercise and maintain balance in your diet. A happy body is a healthy body, not one abused by crash diets and chilli peppers.

About the Author

Michelle is a scientist, an athlete and a writer and she’s proud to have faced her demons head on and she’s beating them. In weight lifting she found an outlet to help change her life – and she’s loving it! Follow her journey with BULK POWDERS™.

Comments are closed.