Well, that's the thing. I'm not malnourished, I just have a very good bodyweight. Overweight, to various degrees, has become the norm. There was just a lot less overweight in those days, mostly because of a suger-poor diet.
Perfect opportunity to share some of the insights I gained from Blazé's memories I just bought: French troops actually probably weren't malnourished most of the time. They were true masters in 'finding' food, and you will find plenty of accounts of them eating themselves completely full to the point where they become sick and become a casualty. Blazé describes how men would take everything they could find, spend all night making food, eat as much as they could and then just leave the rest to spoil, no matter if troops were coming behind them, and that it was common for troops to eat like kings one day and then eat absolutely nothing for the next.