16 minutes... It took me 16 minutes to reach 301 kg with vore off. That a game with 3 inputs where you just have to dodge or eat the objects that appear, a game that lasts 15-20 minutes, seems too complicated or “impossible” to you. That's more your problem than the game's.
You can interpret it in terms of energy: the more energy it recovers, the more calories the food has. Also, all foods except water contain calories, but healthy foods contain only small amounts, yet they still contribute to weight.