How do you stay full?

The healthier the food, the more you can have of it because lower calories.

For me it's getting enough protein and fat that keeps me from getting hungry. See this post for more info: http://www.myfitnesspal.com/topics/show/819055-setting-your-calorie-and-macro-targets

I snack on lots of protein and fiber. They keep you full for longer periods of time. I eat a lot of apples, turkey jerky, low calorie protein/fiber bars and plain Greek yogurt mixed with a tiny bit of powdered ranch or dry onion soup mix. Also, I drink tons of water. The hunger drove me nuts at first as well, especially when I initially started lifting, but my body eventually adjusted to it.

For me it's getting enough protein and fat that keeps me from getting hungry. See this post for more info: http://www.myfitnesspal.com/topics/show/819055-setting-your-calorie-and-macro-targets

^this, for sure: protein & fat are more filling (but try to make them healthy, functional foods). But also make sure he is getting enough water. Sometimes thirst and hunger feel the same. It's not always a parched throat that is telling a person that they are physiologically thirsting. Cutting back on sodium might help with thirst too, but first and foremost is drinking plenty of water often. Other than those things, there could be a psychological component in which he may need to replace eating with some other "joy-seeking", dopamine-producing activity. It is possible to "re-program" so that exercise can be "rewarding" enough to replace food. Or, some kind of playing activity. And of course sex.

2 words ... Peanut. Butter. Lol

I think the problem might be the kinds of foods he's eating - for me, I rarely if ever feel hungry now that I'm only eating real foods (whereas when I joined MFP the first time I was constantly hungry because it's really hard to feel full eating processed foods that are high in calories and low in nutrition). Now my breakfasts are things like eggs and bacon/sausage, maybe some fruit if I'm still hungry (rare), lunches are usually leftovers, and dinners are things like stir fries made with a huge amount of vegetables, usually chicken, and cooked in butter (yummy AND filling).

I don't know what you're normally eating, but as someone else said, healthier food tends to not only be better for your body but lower in calories (there are obviously some exceptions to this), so if you start transitioning towards eating healthier foods, and upping your protein and fat (this really help with satiation, and don't be afraid that fat will make you fat - that's not how it works!) you might find you get to eat a larger volume of food for less calories (or at least more filling food).

I never have a problem going hungry on this kind of lifestyle; at worst I'm not totally full (but I am satisfied and no longer hungry). And there's no feeling of deprivation because it's really easy to make these foods taste delicious too.

Avoiding processed foods and getting plenty of protein & fat works for me, too. I eat 3 meals per day and find no need for snacking.

Fiber, too. Fiber has nothing in it nutritionally, but it has substance to it. I have a glass of water with fiber in it with every meal, and that helps me. Note: He will probably be pooping more often, but that's good for you (As long as he makes it to the bathroom)