Very often when we read one of those articles / studies that explain why diet matters, physical activity does not, we can see that one of the reasons against the aforementioned activity is the fact that the calories burned are often overestimated, for example for activities such as various classes, weight room, crossfit etc.

People who go to the gym, you have to know, fall into two categories : those who are serious and those who slack off. The ones who are serious are also the motivated ones who get results. Those who are sluggish no. The truth is cruel but simple, and it is important as a premise for understanding what follows , which is how to lose body fat at any age .

The more time passes (already after the age of twenty), the more the metabolism slows down : the reason according to experts is only one, that the body tends to reduce lean mass. This happens as we get older. We are born that we are potentially war machines and we have 100% resources on our side, then gradually our body realizes that much of our armory remains unused. So, since the body always thinks in terms of survival, it asks itself: what am I going to do with this lean mass? Come on, let’s lose some on the way. And so as we age we are increasingly weaker, less thin.

Now: metabolism depends on our lean mass, on our muscles. The more we build muscle, the more our metabolism is maintained at a certain level: for every kilo of muscle, the body burns 12 to 20 more calories.
Little, but always better to be more muscular than not.
And, news of the news, one of the ways to lose lean mass is to do too much cardio. 
So, if we train in the weight room or do crossfit or do other anaerobic activities, it must be taken into account that we burn few calories but increase muscle mass, which allows us to have a slightly higher basal metabolic rate. If we do cardio to burn more calories, increase the calorie deficit and lose weight, we run the risk of losing lean mass. If we only do the same diet.

To lose body fat at any age, we must therefore think like this: on the one hand, increase your lean mass by promoting muscle growth, which also makes us toned and lean; on the other hand, do some cardio to increase energy expenditure (half an hour every day, or 40 minutes three to four times a week, at the end of the workout).