Question: why is it more difficult to loose weight than gain it?

Alex Haragan answered on 5 Jun 2018:

Just like Hannah says – we have specific mechanisms in our bodies that keep us like this.
Humans have evolved over hundreds of thousands of years – and its only really been in the last few decades that we’re in a situation to have so much more (food) than we need.
Conventional theory says we evolved as hunter-gatherers. You can break food down in various basic groups – fats, proteins, carbohydrates etc.
If you image a stone-age hunter – mostly eating plants and animals – then carb-heavy foods (like rice, wheat, bread, pasta etc) were relatively rare in their diet.
As a result we developed several enzymes (like amylase) that are super good at extracting nutrients from carbohydrates because they were relatively hard to get.
Our 21st century diets are typically the opposite – very high in carbohydrate and sugar and, for many, too low in fruit&veg and protein etc.
So we have evolved to be very efficient at taking in energy and storing it as fat – and modern diets do nothing to help this!
Losing weight requires you to break down things like fat.
The simplest way to think of it is this:
If you eat 1000 calories in a day, and you use 1000 calories in exercise, you’ll never gain or lose weight. If you eat 1000 calories and only use 800, you’ll put on weight every day. And again to lose weight you need to use more than you eat.
Nutrition is, like everything, much more complicated than this – but its very easy to eat a little bit too much every day, and much harder to regularly have a healthy diet with lots of good quality exercise.
But if you are able to – its maybe only a little harder to lose it than put it on.