The easing of driver weight rules for the 2019 Formula 1 season means this is the first year that Valtteri Bottas has not had a long illness during the winter.
Among the F1 rule tweaks for 2019 is a stipulation that a driver and their seat must weigh a minimum of 80kg.
Previously driver weight was only included within the overall F1 car weight rules, meaning a lighter driver offered teams advantages in terms of balance placement or lower car weight overall if the design was over the minimum.
The rule change means that any team with a driver and seat under 80kg must now add ballast to make it up to that weight.
Bottas said the rules had made a huge difference to him this winter.
"Yes I've been able to actually eat," he said. "It's quite nice to be able to gain a kilo or two. Getting pretty close to my natural weight.
"I think the regs are very good. For taller drivers it makes it easier.
"For many drivers for a long time you've had to be below your natural weight.
"It's very easy to get ill or sick. Obviously the last six years every winter I've had quite a long period of being ill.
"It was the first winter for many, many years I didn't have any flu or sickness.
"I can eat more and make sure when I train I get all the nutrients and recover well. I feel good."
In Melbourne on Thursday he explained that the previous rules had been a constant pressure.
"We do big training camps in the winter and I haven't had to think on every meal that if I have one or two calories too much it is going to make me gain weight," he said.
"So it's been really good to be able to recover well - you sleep better, feel better, feel less ill, because I think in my whole career in Formula 1 I've had to be a couple of kilos below my natural weight and then it's always fighting, fighting at the weight."
Bottas's Mercedes team-mate Lewis Hamilton said last month that he had been able to rethink his training routine and focus on building more muscle mass with the flexibility the rule change offered.