BBC News - Hunter Gatherer Clue To Obesity

The idea that exercise is more important than diet in the fight against obesity has been contradicted by new research.

A study of the Hadza tribe, who still exist as hunter gatherers, suggests the amount of calories we need is a fixed human characteristic.

This suggests Westerners are growing obese through over-eating rather than having inactive lifestyles, say scientists.

http://www.bbc.co.uk/news/science-environment-18985141

In other words - another conjecture down the toilet.

The author's conclusion:
Being active is really important to your health but it won't keep you thin - we need to eat less to do that.

This is a swat in the face to many, those who have long since bought off on the idea that working out is both essential and proven to be helpful for fat loss.  However, the science that has been done is contradictory on the topic.  You can read the two sides of the "exercise for fat all" issue from this post and the two that followed it - the short version is that if you eat foods that send your body into a fat making hormonal bias, exercise is likely to make you hungry, and thus result in an increased food intake.  There are caveats to that statement - if you exercise multiple hours per day, it may be impossible or at least difficult to eat enough to replace what the exercise burns.  However, this is not a great trade for either health or quality of life.  

If exercise didn't make one more hungry, all lumberjacks would have starved to death.  

That said, exercise is very important to living a good life - if you want to live a mobile, vigorous, potent life, you must exercise for the work capacities that you desire.  You should be working for strength, endurance, stamina, speed, power, agility, coordination, accuracy, flexibility and balance.  These attributes can all be enhanced through training, and they will all play a role in living a better life.

In short, eat for health, train for desirable physical capacities, and live well.