The only issue not being discussed is that of Insulin resistance. If you are of normal weight and aren't putting carbs into your mouth 12 hours/day, ignore this comment. Nothing wrong with popcorn and the comments here are right on with regards to seed oil, butter, etc. But popcorn is pure carbs. But if you are overweight, you need to make sure you are going without anything being eaten or drank (exception of water, black coffee or tea) for at least 12 hours/day, 15 or 18 is better. The pancreas secretes insulin when you eat carbs or protein. The presence of insulin restricts the ability of the body to access fat stores to burn, which means that you retain fat on your body. So while cooking popcorn using air and adding butter (or not) is the healthiest way to prepare it, consuming carbs with fat ensures you are storing fat on your body unless you are working out constantly. If you have normal eating habits, no problem. If you are always snacking from morning to bedtime and are overweight, the above description is the problem.