The introduction of the Kinetic Energy Recovery System (KERS) this year has led to almost all driver in Formula 1 lose a lot of weight during the off-season. The reason was quite simple: once a driver would lose from 2 to 5 kilos, the team's mechanics would have extra ballast to work with in order to improve car's balance.
Since the KERS unit has the same placement in all F1 cars – and considering the FIA did not adjust the weight limit of an F1 car despite the introduction of the new technology, believed to weight up to 30 kg – getting the extra pounds of ballast could only come from the drivers' losing weight. Heidfeld admitted never in his life had he watched his eating habits more than the past winter.
“Never in my life had I counted calories. I would not have thought I had anything to lose. But this winter I paid attention to taking in less carbohydrates and fat and I trained harder than I ever have before,” said Heidfeld, according to the aforementioned source.
Teammate Robert Kubica, Ferrari's Kimi Raikkonen, Renault's Fernando Alonso and Williams' Nico Rosberg were only a few drivers who have lost several kilos due to the same reason.
There were, however, a few drivers who not only did not care about the prospect of improving their car's performances as a result of weight loss but actually gained a few kilos during the winter. Red Bull's Mark Webber and Sebastian Vettel publicly announced “diet” was not their favorite word this winter, while Renault's Nelsinho Piquet admitted it was impossible for him to lose any weight during the past months.