You know the story: in Forge of Creation, 16-year old Ben magically encounters his 10-year old self which due to his self-hatred issues ferociously attacks him. High-school student doesn't take him seriously and effortlessly grabs him by T-shirt. HOW??? According to New Health Advisor website, 10-year old can weigh up to 100 lbs which 45 kg. Judging by his height (presumably 5'5-5'8 tall), weigh (probably 50-60 kg) and slender build, Ben probably shouldn't be able to lift 45 kg in just one hand without any effort, especially when 10-year old Ben was trashing around.
On the other hand, 16-year old Ben has demonstrated several times that he clearly isn't a human. Dude took a blast of nuclear energy to the chest and large stone bar falling on him in Deep episode, leapt at the height of at least 30 ft in Mystery, Incorporeal and who knows what else.