10 Reasons Skinny People Don't Gain Weight Slideshow

It might be hard to believe, but some people don't pay attention to how much food they eat in a given day. This unawareness leads to an underestimation of calories consumed. Keeping track of how much you eat throughout the day allows you, for instance, to make up for that lunch of a cheeseburger and fries with a lighter dinner. 

Hormones play a significant, but often overlooked, role in regulating body weight. For example, individuals with higher leptin sensitivity tend to have an easier time losing weight and controlling cravings. Leptin, also known as the "starvation hormone," is a protein that tells the brain if you have enough energy stored in your fat cells to complete your normal metabolic processes, such as breathing, circulating blood, etc. When leptin levels are above a certain point, the body burns energy at a normal rate, but when below, the body conserves energy and stimulates feelings of hunger.  Some people can also be leptin resistant, meaning that the body doesn't respond accordingly to the brains signals.

There's a big difference between hunger and appetite: Hunger is the physical need to eat, while appetite is psychological desire to eat. If unfazed by the smell of freshly baked bread or the sight of ice cream, than there is less of a risk that you will cave-in to cravings.   

Click here for eight foods to naturally suppress your appetite.  

A "set point" is the range of fatness or weight that the body is naturally programmed to maintain over time. But set-points can differ for each individual, even for those with the same height and body type. People whose bodies have naturally low set points are less likely to crave food when close to their ideal weight and will barely gain any fat despite over consuming calories.

Click here for nine foods that will help you keep weight off.

NEAT, or non-exercise activity thermogenesis, accounts for all these calories burned from daily movements that don't qualify as traditional exercise. Increasing your NEAT involves simple routine changes like taking the stairs, walking to lunch, or using a standing desk. These movements are difficult to pick up on unless you're following someone around for a week, but these burned calories can significantly contribute to weight loss.

Some people care a lot about looking trim, and although they might not diet or engage in a daily exercise routine, they still prioritize maintaining a certain weight. This mentality isn't always obvious to the casual observer, and might contribute to the feeling that someone just doesn't gain weight. 

A full night's sleep is crucial to weight loss. A lack of sleep leads to the production or cortisol, a hormone that induces hunger, and makes it more difficult for the body to metabolize carbohydrates and burn fat. Scheduling a consistent wake-up time and exercising are two simple ways to a more restful sleep.  

Weight gain isn't as much about food quantity as it is food quality. Skinnier people might eat greater volumes of food, but if it's less caloric and nutritious, than they still won't gain weight. Eating foods of minimal nutritional value, such as candy bars, soda, or highly processed baked goods doesn't make you full but does make it more difficult to eat less going forward. 

Click here for 12 foods you can eat as much as you want of and still lose weight.

Although some factors contributing the weight gain are physical; others are psychological. It's estimated that each day we are forced to make over 200 food-related decisions — ample opportunity to make a mistake. While some people might have amazing self-control concerning other aspects of life such as smoking, drugs, or alcohol, if they can't resist the urge to eat, they will most likely gain more weight.

Click here for 10 mind tricks to fool yourself into eating less.

Have you ever watched an eating competition where a daring individual attempts to shovel four, five, or even six pound of food into their mouth in under an hour? If you have, you'll notice that they can only stuff their face for around thirty minutes; because this is the amount of time it takes for the brain to register the chemicals signaling that the stomach is full. A slower eating pace means you will eat less, while still feeling full.