Santa Claus's apparent weight gain, much chronicled in the popular media, raises the question of whether his jolly persona could be at risk. We investigate why Santa remains jolly, even though he is becoming obese, and what factors could be keeping him upbeat. Measures of body mass, mental health and physical activity were collected from a representative cohort of Canadian adults surveyed in 1988 and again 15 years later. Remaining sedentary was generally associated with a low jolly quotient (JQ). In addition, a "healthy weight" pattern and remaining "sedentary" was associated with higher odds of a low JQ than remaining or becoming obese (from overweight) while staying active. Although mechanisms for understanding how Santa remains active are yet to be elucidated, we have uncovered a few clues and conclude that Santa indeed remains jolly particularly because he is active, and that a GIFT (graduated intensity fitness training) is good for combating the "Santa Too Fat Blues."