Experts claim that weight gain is caused by many things. Thus, the extra body fat you may be carrying is likely the result of a multitude of factors.

In an effort to explain excess body fat, scientists have come up with some theories. And although these theories aren’t set in stone, they may provide some insight as to why you’re gaining weight.

So without further delay, here are potential explanations for why you’re carrying extra weight:

1. LPL. Also known as lipoprotein lipase, LPL is responsible for storing fat in your fat cells. Proponents of this theory postulate that people with excess body fat have a higher amount of LPL. And that those with lower levels of body fat have lower levels of LPL.

2. Fat cell number. Not only do fat cells increase in size, but they also increase in number. When you’re young, your fat cells have the highest replication rate. This theory states that heavier people have a higher number of fat cells and therefore are more likely to store food as fat.

3. The regulated point. According to this one, your body has a certain weight or set point that it tries very hard to stay at. Any effort on your part to change will be immediately thwarted by metabolic slow down.

4. Less calorie burning fat. The fat responsible for excess weight gain, white fat, mainly stores calories. Brown fat, however, mainly burns fat to release heat. Individuals with higher levels of body fat have less brown fat.

5. Calorie burning from eating. Food has a thermic effect. Some foods have more of a thermic effect than others. And this theory claims that lean people will burn more calories right after eating in comparison to heavy people.

The causes of body fatness are many and it’s very hard to point the finger at any single cause. Having said that, knowing the possible mechanisms that could potentially be causing your weight gain doesn’t hurt. The take home point here is to look at weight gain from many points of view.