I'm not an expert, but my understanding is that eating lots of sugar and fat is a worst-case metabolically for gaining bodyfat. Your body will prioritize sugar

I'm not an expert, but my understanding is that eating lots of sugar and fat is a worst-case metabolically for gaining bodyfat. Your body will prioritize sugar for energy while it's in your blood stream, so if you have lots of both, your body will just store the fat.