[dreistdreist]

Nothing, I'm in great shape.

Understand the basics of nutrition, mainly calories in calories out. I (and many people I know) often move 5 or more kgs up or down in preparation for a tournament with weight classes. It's really no big deal if you track your calories.

I'm always surprised how people struggle with losing weight, it's really not that hard to do.

Do some sport that you enjoy regularly that covers your cardio and lift some weights. Eat somewhat healthy, but mostly watch how much you eat.

[dagw]

I'm always surprised how people struggle with losing weight

I'm always surprised how people struggle to quit smoking. I smoked a couple of cigarettes, once, and then just stopped. It's really not that hard to do.

[dreistdreist]

I might have to clarify, I wasn't talking about obese people who are addicted to food. I was thinking more about all those people who "just need to lose 5kg" and yet 2 years later they are still the same weight (or heavier).

Addiction is a different problem, but losing weight itself is easy if you track calories (I know lots of people who claim the opposite).