What you eat and how much you eat is largely a function of what is available in your environment. When is it more difficult to avoid eating cookies? When there's a plate of fresh baked cookies on your kitchen counter? Or, when the nearest cookie is at the bakery two miles from the comfort of your living room?
Most people have a simple relationship with food, the "see food, eat food" relationship! If you don't have a plan, the world has a plan for you! And the world's plan is high in fat and calories, and low in physical activity--a guaranteed recipe for weight gain. Successful weight control in modern America has never been more challenging. There was a time when Americans ate three meals a day, and the prevailing wisdom was, "don't snack between meals--because you'll ruin your supper." Our former traditions and expectations supported healthier eating habits, while our current environment provides us with endless opportunities to overeat (and usually on the least healthiest choices), as well as be more sedentary.
The people who will be successful with their weight long-term are those who fundamentally change their home environment through stimulus control. Weight Loss Mastery Skill #4 is Stimulus Control. They also learn to plan ahead when socializing by communicating their needs, and if necessary, they’ll bring beverages or snacks with them. They don’t assume, or hope, that things will “work out” – they accept that they have to MAKE things work out.