It's well known that some people seem to be naturally skinny. While some agonize over calorie counting and exercise to maintain their figures, others hardly have to pay attention to their diets to stay slim, all while staving off chronic disease. Now scientists say it's not just luck, but could actually be down to a single 'skinny gene' that may help thousands of Americans keep excess weight off, even without dieting or GLP-1 drugs.In a new study, researchers looked at Folliculin Interacting Protein 1, or FNIP1. Normally this gene regulates cellular energy and metabolism, controlling how cells burn or store fuel.But one in 7,000 people, or one million worldwide, carry a broken copy of this gene that means the body burns calories more easily.The team, from Regeneron Genetics Center in New York, analyzed genetic data from more than one million people across three continents, finding 150 participants with an FNIP1 mutation. Researchers found those participants had lower blood sugar, decreased cholesterol, less fat around their livers and about a 60 percent lower risk of metabolic conditions like obesity and diabetes.This had nothing to do with classic weight loss measures like diet and exercise. Instead, they were simply burning more calories due to the mutation. A rare gene mutation has been shown to help burn more calories, aiding weight loss and reducing the risk of heart and other metabolic diseases