What Do You Do When You're Injured?

He's told me absolutely no exercise for at least a week, and then gentle walking, water exercises or recumbent cycling for at least two weeks after that.

This. Yes, it does suck. Injuries need time and rest in order to heal.

But let me counter this with a rhetorical question: how long will you be laid up if you ignore it and aggravate the injury even worse than it is now? How much less activity will you be able to do if a muscle tear becomes blown ligaments and torn cartilage?

There will be other races. You only have one body.

Hi,
I'm in pretty much the same situation but I've injured my knee, was boxing, spinning, running, weight training 5 days a week and now I can do nothing it's driving me nut, could be out for several months!!
I wanted to keep up exercise so Dr recommended swimming and upper body weights only but I found that still aggraved my knee, have been on total rest last 2 days and it is feeling a little better. It's hard to accept but sometimes you need to take time off to let your body heal.
I would agree with your dr, total rest for a week, and then lower body only exercise such as recumbent bike or hill walking on treadmill. When it feels better, still take it easy for a few weeks don't jump right back to where you left off.
Re the calorie level, I would aim for losing maybe 0.5 lb or even maintain. I was set for 2lb week with exercise, 1lb without. Last week I gained 0.8 think that was due to the sudden extra cals from not exercising, but this week it's creeping back down. For me I'm more hungry when I don't exercise for some reason so cutting cals further will not work for me, I'm interested to see what I lose with keeping to the higher cal level!

Rest,,,focus more on nutrution

This....and as you've mentioned yourself. This could also be a good time to focus on maintaining rather than losing, give your body whatever it needs to recover in the best possible way. In the end this will probably get you back to 100% a lot faster than trying to press on.

In my opinion (and I don’t have science to back this up) the most important part of injury recovery is the early days. The better you can rest in the first few hours and days the quicker your recovery will be.

So, in your position I would be off exercise for the recommended 1 week and take it easy for the next one at least. I’m being vague about the second week on purpose because how well you feel during that week is going to be a major factor.
With respect to your race if it’s a few months away, taking a couple of weeks off now is not likely to impact on the race massively (if at all).

Gentle exercise is going to depend upon what causes pain (I’m not one for taking painkillers, I like to know when something is causing pain so that I can stop it! but if you are in continual pain I can see that taking a tablet is going to be the only option) but in the first week I would try to get out for a 40min to 1 hour walk per day (I’m basing this on the fact that you are already fit and used to spending a decent chunk of your day exercising and you need to get out to keep you sane), obviously if walking gives you pain don’t continue with it. Next week if you can get to the swimming pool you could try power walking in water. I’ve done it a few times and because you can’t move very quickly there is very little upper body work considering the lower body effort.
Food, if you are looking to continue weight loss 1300 sounds sensible.

Best wishes with it.

I was going to suggest the same. Having said that, give your body as long as it needs, it's counter-productive to push it while it needs to heal.