My friend has a "fat" lad, he's 11m now and eats everything. He's the same size as his big brother, 18m older than him. But he's developmentally fine, he's not so fat he can't crawl or cruise (a worry before he did start crawling!), he's just hungry. But he sleeps through, so you can't complain!

DS is on the skinny side, he is a picky eater though, doesn't sleep well and is always on the go. Even jumping about in the baby carrier or my arms. Both boys are fine. Some babies are just bigger than others. You'd get comments the other way if he lost weight.

There is nothing wrong with Nixon if he's developmentally fine (which I believe he is). The time to worry about weight gain is when you have finished growing (generally, there are execptions) but not as a baby or a toddler. What crazy society thinks we should put a baby on a diet?