I would be careful with exercise on SS....I used to exercise a lot before I did CD, it helped me maintain my weight (fat as I was lol). When I started doing CD my CDC warned me against doing too much in the first few weeks while I got used to the diet. I listened but a few weeks in I decided to get back out there and exercise again. And my losses slowed down. It's to do with cardio exercise.
Too much cardio can actually have a negative affect on your weight loss and slow it down. It's to do with the way your body obtains it's energy. I'm not saying don't do exercise, just do less cardio and more resistance. The reason for easing up on the cardio is:
It's to do with how your body uses the energy during exercise. When you go on a diet your body starts initially using up it's glucose stores, then glycogen which is stored in the liver, and finally fat. By being on a VLCD and in ketosis you should have very little glycogen stored away so your body burns fat.
Which is exactly what we want, BUT if you then go adding in strenuous exercise your body thinks something is amiss and reserves fat incase it needs it. The human body has no idea that you're doing cardio because you ate a curry or had a bad day, it thinks that you'll be doing the extra cardio etc forever and you'll need reserves to maintain the energy needed to actually run, cycle etc... not good when we want to be burning fat not storing it.
That's as much as I know about it, I'm in the middle of learning about all this as part of my plans for maintaining so it's all a bit new to me, hope I explained it okay.
My CDC seemed to think it was common that people who did a lot of cardio had lower losses.
Exercises such as light weights help build lean muscle which in turn helps burn fat more efficiently and gives better definition and tone to your body shape.
Hope that helps. I