Unfortunately, the lead of the article seems to imply that calories don't matter. If you read the article a bit more carefully, you would see that they do, because, the foods that lead to weight gain are high caloric and those that do not lead to weight gain are naturally less caloric.
So what foods lead to weight gain? According to the article:
The foods that contributed to the greatest weight gain were not surprising. French fries led the list: Increased consumption of this food alone was linked to an average weight gain of 3.4 pounds in each four-year period. Other important contributors were potato chips (1.7 pounds), sugar-sweetened drinks (1 pound), red meats and processed meats (0.95 and 0.93 pound, respectively), other forms of potatoes (0.57 pound), sweets and desserts (0.41 pound), refined grains (0.39 pound), other fried foods (0.32 pound), 100-percent fruit juice (0.31 pound) and butter (0.3 pound).And the foods that lead to weight loss?
Also not too surprising were most of the foods that resulted in weight loss or no gain when consumed in greater amounts during the study: fruits, vegetables and whole grains. Compared with those who gained the most weight, participants in the Nurses’ Health Study who lost weight consumed 3.1 more servings of vegetables each dayAdditionally, the study said that dairy had a neutral effect on weight gain/loss and those who ate the most yogurt and nuts experienced the most weight loss. Also interesting was that metabolism slows with the consumption of refined grains, but stayed the same with the consumption of whole grains.
As I indicated above, I think calories do matter. This study basically proves that if you eat high calorie foods, you'll eat more to feel sated, and gain weight. If you want to avoid gaining weight (or lose it) you need to fill up on low-calorie fruits and vegetables.
Period. End of story.