Why am I fattening? The million dollar question that everyone asks themselves when they realize that the partner is able to eat a musk ox without taking a hectogram, the best friend makes a pizza sandwich and her belly is always flat , the colleague eats at the fast food restaurant on his lunch break but remains normal weight. And the answer to the question “why I’m fattening” almost always turns out to be: maybe I’m predisposed, I was born like that. With a tendency to gain weight.
But an English study gives us another answer to the fateful question: why am I fattening?
That is: because of your gut.
How do you understand that genetic predisposition, except in the case of rare diseases, has nothing to do with how much and how your body packs kilos? Simple,conduct a study on twins only. 

Monozygotic twins. Those who often have a sadistic taste to dress in the same colors at school, so you don’t recognize them. Those that you really have to force yourself to look for a slightly different tone of voice, a more or less marked smile, or you don’t recognize them. Never. Do you know what the reason you don’t recognize them is? They have the same genetic makeup. 
If one had a “predisposition to gain weight”, the other would have it too. By force.
And so a group of scientists from King’s College London’s Twin Research Group, led by Professor Tim Spector, known for studying diet myths and the correlation between diet and gut health, analyzed the intestines of 500 pairs of twins.Thin, fat, of normal weight. And they found that only about 17% of cases had a real genetic predisposition to obesity. In all other cases, so less than two out of ten, the problem for which he gained weight was the intestine .
Gut bacteria that are altered by poor food choices, use of drugs and supplements, alcohol, smoking, and so on, cause you to be overweight.  A diet based on probiotics and intestinal “friendly” foods or particular drugs can change this trend, and make us lose weight. To find out more, read the intestinal diet.