I like to run because:
1 I just enjoy the act of running.
2 I enjoy competing. Competing against others and competing against myself.
Most of the runners I know run for similar reasons. There are others I know though, who do not like competing and just enjoy going out for a run with no specific goals in sight. There are also a few people I know who use running as part of a weight / body shape management programme.
Those that I know in the latter group are all intelligent, sensible people who are aware that running (or any other exercise) is only a part of what they need to do to loose/maintain weight and or body shape and maintain their general fitness.
Yet, today saw the report in the 'news' (http://www.pa.press.net/) of a recent study under the headlines of "Exercise won't cure child obesity". The article goes on to say that "Scientists have questioned the assumption that a lack of exercise causes fatness in children." The article then follows with "Researchers said the findings indicate that nutrition, rather than exercise, is the best way of tackling childhood obesity".
Surely it is common sense that obesity, childhood or otherwise, comes from other contributing factors such as poor nutrition and not just lack of exercise. Exercise and nutrition are only a part of a holistic process.
Otherwise I would be eating 10 Big Macs and drinking 10 pints of beer a night - safe in the knowledge that I would sweat it all back out during my run the next morning.