But there are some exceptions ... and tonight's American Football game between the Chicago Bears and Tampa Bay Buccaneers featured some excellent examples!
Whilst most of the players looked muscular but athletic, a few of the defensive players had some substantial spare tyres! Despite all the kit they just didn't look like athletes and certainly weren't healthy looking. Top of the charts was J'Marcus Webb of the bears, weighing in at 333 pounds - 3 times my weight!
But these players aren't accidentally this heavy - to be a defensive block you need to be hard to knock over and basically act like a human wall ... being light on your feet is of no help!
What all this illustrates is that being sporty doesn't necessarily equate to being healthy, even though I think a lot of people think they do. Infact in England sport and unhealthy habits often go hand in hand, rugby teams post-match pub crawls, rowers post-training fry ups and generally eating large amounts of sugary foods in the name of 'carb loading'.
Being sporty is great, but just because you're burning off more calories than the lazybones at the desk next to you doesn't mean you can eat more chocolate or biscuits.
Certainly it's important to up your calories if you're training alot but not through loads of sugar - infact the more you train the higher nutrient intake you need so eating the empty calories in junk food is counter productive.
But there is one exception to this which gives you an opportunity to satisfy your sweet tooth. Post intensive exercise (60minutes plus) you should have a high GI recovery snack within 30minutes to replace glycogen in the muscles and reduce recovery time.
Alot of sports people will use sports drinks, but if you fancy a sweet treat then this is the time to eat something sugary. It should still be low-fat so could be a sugary cereal (frosties, crunchy nut), white toast with jam, a low-fat muffin, sweetened yoghurt or even sweets (yes even Haribo!). As a guide this snack should contain one gram of carbs for every kilo of body weight, per hour exercised. So for me that would be 51g of carbohydrate after a one hour spinning class (I weight 51kg).
The good news is that this post-workout snack won't just improve your recovery time, by reducing exercise related fatigue, it can also help bring down the levels of the stress hormone cortisol, which is produced in response to intensive exercise. Cortisol encourages weight gain round your waist, so doing a lot of intensive exercise can infact encourage central weight gain and by having a sweet treat after exercise you're less likely to develop one of the substantial guts that I saw at tonight's game - sweet!
ps the Bears won :-)