People gain weight because they 1. eat poorly 2. lack proper nutrients 3. are usually fairly stationary 4. eat meals consisting of animal feed.
Let's think about this logically. Livestock grazes on open fields of green. Come right before the trip to slaughter, they pull them from the fields, which removes the exercise component and the fresh/whole nutrition. Instead they start feeding them corn and dried grains. Why? To fatten them up for maximum profit.
So, if you want to lose weight, cut: 1. all grass/grains - especially wheat, rye and oats (your body can't digest these). 2. Breads, crackers, battered, sweets, cakes, cookies, pies, etc. 3. SUGAR, especially white useless sugar. Replace with Stevia (no glycemic blip from the stuff, unlike honey, molasses and other alt sugars)
You should also stick to a strict eating meal time. Advising a large breakfast with carb emphasis and lower on proteins. Then throughout the day, light healthy snacks, no chips, dips, pretzels, candy, etc. Instead try fresh crispy foods... Apples, pears, carrots, etc. If you must have crunch, look at nuts. Dinner should be protein high and carb low. Eat at least 3 hours prior to sleep. Again, evening should be none of the bad snacks.
Other big space no one seems to look at today is beverages. If you consume soda pop in large doses, it's ugly outcome for you in future, especially if you consume the "diet" versions --- which tend to ferment in your stomach and are highly toxic. Replace those with green tea, other teas you might like, spring/mineral water, lemonade (fresh squeezed), good coffee. Fresh brewed from bulk or tea bags. Local honey or stevia for sweetener.
Folks don't talk about it, but the reason why people are so hungry so often is because your food, even the good organic yuppie varieties are usually devoid of key nutrients. Most of what you consume is water and ash content. Your body wants building materials, so it signals that you are hungry again. Since food isn't going to fulfill your needs, you MUST supplement with bio-available vitamins and nutrients. There are tons of options out there, more than ever.
Finally, introduce exercise, regular exercise. Like running to the corner store for supplies or biking to do errands. Yard work is another good option. Swimming at the local pool is something everyone can do.