Kinect Sports

There is a very easy way to get all the DLC achievements without breaking sweat :

1. Stand in front of your Kinect sensor as normal
2. Hold a curtain or sheet in front of you so that the bottom of it touches the floor
3. Move the sheet sideways, dragging the bottom of it from left to right (and back again!) along the floor

You will get between 0.30 - 0.50 kcals/second by doing this.. !

To get this you just need to beat the milk and banana in a single session. In other words don't turn off your Xbox once started.

Tips:
You can get calories before and after an event finishes
It works on movement so wave your arms and move about a lot the more you move the more you burn.
Wave as much as possible and don't worry too much about the game itself
run from left to right while waving no matter what the event this helps
Some games you can burn calories without starting the game, I would do this a little to boost your score but not too long as you still have to wait
Having a second player take over helps on the harder foods.

If you have beaten the target and the timer goes over, don't worry it normally allows one final game before finishing.

If you have anything to add, leave a comment and I'll improve this solution.

Thanks to GLORIXJIM for these further tips:
- you can calculate the average kcal/min you need to beat your opponent. The running games will give you the opportunity to get way past that number (20-25 kcal/min), while the light and medium stuff sometimes nets you only 3-7 kcal/min. To beat the pizza, you must average almost 8 kcal/min.
- The second player is a great way, but you can also use your GuideButton to pause the game- time DOES stop.
- I think you will burn calories after the game, regardless of moving or waving your arms.
- for some games, waving your arms (and running left/right) seriously increases your kcal/min average.
Like the volleybal related games, you score more points/kcals running left and right, waving your arms then really trying to hit/dodge the fruit. The score while standing still and catching the fruit with your feet/hands/head is a poor 0.03 kcal/second!