I think we can be too quick to demonize comparison and make the judgment that we should NEVER compare ourselves to others. There is a difference between the idea behind "Comparison is the thief of joy," (quote attributed to Theodore Roosevelt)-- which can absolutely be true when we covet the life others have, or hold ourselves to unrealistic standards.
But there is another way in which comparison can PUSH us, help us strive for more, and recognize that there are ROLE MODELS we can look up to! Being healthy can be tough, it can be hard to be consistent with a workout routine when you're exhausted, or make another meal when you are sick to death of cooking. This is where I look to those who ARE doing it, and doing it joyfully, and think- "If others can, why not I?" (quote usually attributed to St. Augustine).