Why even after eating heavily few persons remain thin do not put on weight at all?

We all love foods and consume variety of delicious foods in our daily lives. After some point of time some of us become fat while others remain thin and lean. It is common that those who have become fat and bulky often feel jealous about others who have remained thin. It is often said that those people who remained thin even after eating so much were blessed more than others.  Have you ever thought about the reason why some remain thin and lean always?
There are few reasons that could make a person appear thin and lean always.
Absence of fat enzyme 
Fat present in the human body gets regulated by a digestive enzyme known as ‘MGAT2’. This enzyme is not present in skinny or thin people. Hence when these people consume heavy foods they might not put on weight unlike others. Body cannot utilize fat that helps in preventing obesity.
Leptin sensitivity
It is known that fat is stored in adipose tissues and leptin is a hormone made by adipose cells. This starvation hormone leptin sends signals to brain about the amount of energy that is required by the body every day. The leptin sensitivity is higher in thin people and these people could lose weight easily and they could also control their food cravings easily. So even after they eat heavily these people appear thin and lean.
Health problems
Many health issues like nutritional disorders, hyperthyroidism, diabetes etc could result in loss of weight in persons and weight gain is prevented. Hence if these people consume huge amounts of food they would not become fat.
Genetics
It is known that the genes pass on from the parents to their kids and being lean and skinny could be due to their parents being lean and skinny. Duplication and absence of chromosomes play an important role in weight gain etc. A person would not gain weight when there is duplication of chromosome whereas when the chromosome is absent then he/she is likely to gain weight.
Lack of proper sleep
Sleeping well is very essential for the overall health. The studies have shown that lack of sleep could stimulate cortisol hormone and finally obesity takes place.