Unless you don't feel well, maybe you are just a skinny person. Like me. I'm 6'1", 170ish(+-5#), cook all day, run 2 mi. daily, exercise, eat when I feel hungry, 90% healthy stuff, drink alot of beer, etc, and am mid 40's. I'm just incapable of eating regularly, not interested. A day might be coffee for breakfast, fruit in late morning, sandwich or salad mid afternoon, a snack somewhere in there. One thing I do maintain is intake of water, and teas. I also find sleep is a factor on my appetite.