I suggest a study of workers that travel a lot long term and short-term to provide highly detailed insight. As there's people that can eat 5000 calories a day and gain nothing; meanwhile, another can eat 1200 calories a day and continuously gain according to metabolism and and other conditions. That leaves the types of environment and activities. As for years, I have seen many healthy/fit workers that are over the road a lot; after a few years, develop spare tires or health issues. As much as physical issues, most work vehicles are not ergonomic on the body, much less passenger cars long term. The type workers do not have a lot of options, they think, as for meal types and end up consuming a lot of fast food on the quick go. Nor take proper efficient breaks from pushy bosses. Treatment and effects versus workers in the office setting. Longer hours versus short hours. Even eating once a day seems to bring the same results. Over a few years time on that cycle, it seems that sugar maintenance and fatty liver disease become prevalent. I witnessed people a 100 lbs never gain weight but develop the problems. Then again, seen a person 100 lbs become 300 lbs at the same rate and amount everyday. The only common denominator seems is where the food comes, job, rest and how it is made and sources. Always in association with almost irreversible health risk that continues to get worse over time. Even when the diet is corrected, once the problems develop, unknowingly started. Seemingly does not stop. As many can have no symptoms and later start having irregular lab test.Also dependent on the person and other underlying conditions or smoking. Where? Especially meals from the like of McDonalds and such. Meals from those places seem to really advance health and weight specially more as much as sugar, kidney and liver problems. Even short term studies on the effects of the food Giants, users put on spare tire weight quickly, developed blood pressure issues and a range of other health problems from one meal a day. Not as much as it just fast food but food that is not made the same as home. Being highly chemically processed with high amounts of fat and sugars to create bulk and taste versus the pure thing. Where profiting from less is more.