I'm not an expert at anything gecko, but I can tell you in the past 3 weeks my gecko has been putting on weight just by eating a varied diet... and a large one.
He eats probably close to 75 - 80 individual insects a week. His diet is mealworms, Dubia Roaches (most recently) Crickets, and silkworms. When he first arrived, I realized he was very skinny so I feed him once in the morning and again at night. He does eat everything, and seems to have an appetite for more. At first I was nervous about how much he was eating, thinking he was over eating or might get an upset stomach but so far, he's gotten past a full shed with no real issues.