With correspondent Tom Costello's Friday story on marketing to the heavyset still in mind [LINK], I got a good taste over the weekend of one of the root causes of obesity in our society. The occasion was my younger son's seventh birthday. Because it rained all day Saturday here in the New York area, we postponed his party, which was to have included lots of outdoor activities.

Instead, we did something we rarely do on weekends: we went out to lunch. As we walked into the restaurant, a popular barbecue place, we passed a man, to put it delicately, whose mid-section required him to be several feet from the table from which he was practically inhaling his lunch. I wondered how he got this way. I noticed several very young children at the table and worried for a moment that health problems related to his obesity could cut the man's life short.

We sat down and read the menu. My wife and the birthday boy decided to split the southern fried chicken. Our other son, who is 10, went for the "fried chicken fingers" from the kids' menu. I ordered a beer and a pulled chicken BBQ sandwich.

As we waited, I noticed other diners coming in. The majority, young and old, men and women, were significantly overweight. They walked slowly to their tables. They looked at the menu. They ordered.

Our food came. My sandwich was a medium pile of barbecue chicken on an open bun, with French fries and cole slaw on the side. It looked manageable, even though a little less would have been no insult. The southern fried chicken -– half a large chicken cut into pieces -- was more than enough for two people of any size, and we ended up taking one of the bigger pieces home. But the real revelation was the chicken "fingers" from the "piglets' menu." This $5 meal came with five, two-inch by three-inch pieces of fried chicken breast and French fries.

Our 10-year-old, who has a healthy appetite, was able to eat just one of the entirely misnamed fingers. "I felt so full after that," he recalled later. "Now I know how fat people get fat. You're so full but the food is so addictively good that you can't stop eating it." And that, I thought, must be the essence of the problem. Keep them eating. Keep them wanting it. Keep them coming back for more with huge portions that will make them think they're getting their money's worth. Servings half the size would have been adequate for each of these dishes. Instead, here was the super-sizing of America unfolding before my eyes.

As I finish writing this, it's a little after seven on Saturday evening. I haven't had a thing to eat since lunch and I'm still not hungry. But it doesn't matter. It's time to cook dinner and I will sit down to eat anyway. Eating is habit, and habit is a hard thing to break. From what I see, marketing to the heavyset will, indeed, be a real growth business.