That’s a textbook sumo bod and for a moment there I mistook his briefs for a mawashi. It’s a lot of work to build up and maintain that but it is doable. You’ll need to exercise heavily, not only with weight training but cardio as well, and before eating so as to not burn the calories you’re taking in, and you’ll need to eat a LOT of food rich in protein and fatty acids which may or may not align with your preferred foods - calorie intake would be primarily through volume, not density. I’d definitely recommend looking up the traditional sumo training regimen. You’ll also have to keep up the training for as long as you stay big. What often happens to retired sumo wrestlers is that their muscles will immediately start to atrophy and they start to suffer from the various known problems associated with unmanaged obesity unless they work to lose the weight.