Can you actually gain 60lbs while pregnant with only 1 baby?

My math teacher was explaining how misleading data helps weight loss products makes money. She gave an example by saying 'I lost 60 pounds in 6 months using this product'. Everyone gasped. Then she said "little did I tell u I started this product 8 months pregnant with my son. I actually gained 60lbs while pregnant. I actully did I am not kidding you, a company would use me to trick people into thinking they would get those results. That's how it was misleading". My question is if that is even possible (to gain 60 lbs while pregnant)?