While the new cars have smaller engines, other changes to the formula (like larger batteries) mean that the cars are heavier overall. Yet the minimum weight limit has apparently not been adjusted proportionately, forcing teams to look even harder to trim excess weight. And when everything's already made of carbon fiber, there's not much more weight to cut, so the onus falls on the drivers.
F1 drivers dangerously losing weight to improve performance - Autoblog
How hard can it be to foresee this outcome? Seems like a piece of cake to mandate a ballast system to counter any advantages from weight and center of gravity because of differences in physique.
Adrian Sutil: lighter Formula 1 drivers blocking weight rule change - F1 news - AUTOSPORT.com
F1 ace Jean-Eric Vergne hospitalised after Australian Grand Prix due to weight loss | Mail Online