Is weight loss simply a case of calories in versus calories out?

Richard Kelly 27th July 2020

According to the science the only way to lose weight is to burn off more calories than you consume.  Weight loss is simply just an equation.  But if it truly is as simple as that, then why can’t many people successfully do it?

In reality this equation is not as straightforward as science would make it out to be.  Calorie counting is not an exact science.  There is plenty of doubt surrounding the calculations used to determine how many calories carbs, proteins and fats contain, with a number of people calling for the amounts shown to be changed.  One gram of protein, for example, is considered to be four calories.  But, due to the thermic effect of protein on the body, it’s often considered as three calories. 

You also have the fact that even on production line products, such as bars or protein powders, the grams and calories is a rough approximation.  No mix is perfectly uniform.  As a result of this the calories shown on packing are allowed to have up to a ten percent variance.  That’s very significant, because with most people ten percent under maintenance would typically be where they were targeting being. 

With real food it’s even more challenging.  A medium apple has ninety-five calories in it, but what size is a medium apple?  When measurements were first down what we consider to be a standard size apple now probably was a large apple when the calorie measurements were first taken.

On the other side of things there is no truly accurate way to measure calorie burn. Fitbits and apple watches are fairly accurate, using heart rate to understand activity and then using that to calculate calorie burn, but if you don’t use one of those then the information you are getting on calories burned is very general indeed. 

So if the equation is generally compromised, how can we trust it to tell us whether we are in deficit or not?  The best singular way is to weigh and make your food yourself and start off by targeting maintaining weight.  That at least tells you pretty accurately the calorie intake you are regularly consuming.  As long as you stick to a period of time on roughly the same number of calories each day you can start to gauge whether your activity and calories are in line.  From there you could choose to lose weight by either increasing activity, or by reducing calories.  Knowing this for yourself gives you back the control of the situation, rather than relying on the amounts the apps are telling you, you’ll know the amount you burn from your metabolism and the impact an hour’s walking has on your results.






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