People who bike to work are on average five kilos lighter than people who take the car:

• Flint, Ellen et al. Active commuting and obesity in mid-life: cross-sectional, observational evidence from UK Biobank. The Lancet Diabetes & Endocrinology , Volume 4 , Issue 5 , 420 – 435. Abstract here.

People who cycle to work also have a 40% lower mortality risk, even if you correct for all positive and negative factors that influence this relationship. 

• Lars Bo Andersen, PhD, DMSc; Peter Schnohr, MD; Marianne Schroll, PhD, DMSc; Hans Ole Hein, MD All-Cause Mortality Associated With Physical Activity During Leisure Time, Work, Sports, and Cycling to Work. Arch Intern Med. 2000;160(11):1621-1628.