You would agree that that is mostly healthy food? And he is eating very large quantities of it. He is not fat, but people who do not do a lot of exercise could eat the same amount of food (or even half, he eats 12,000 calories a day) and gain quite a lot of weight.
Also a diet needs more than fruits and vegetables to be healthy at all.
I agree that there should be less focus on processed and fast foods, but that alone does not eliminate the problem of people eating a lot of food. I could eat a big mac and medium fries for every meal and not gain a lot of weight (3x big mac (563 calories) = 1689 calories + 3* fries (333 calories) = 2688 calories. Which is around the 2500 calorie range for an adult man. That would in no way be healthy, but I would not gain weight quickly.