Appropriate pregnancy weight

I'm sure some of you are familiar with that phot of the model who was 8 months pregnant but only gained about 9/10 pounds. Many people thought it was vanity or she was restricting her diet, come to find out she wasn't and had healthy baby a little over 8pounds. Now for this next part don't roast me but it has me asking the question, are the majority of pregnant women enormously overeating and justifying it through pregnancy?