This is a little gross. If you don’t want to read about my sweat, you might want to skip this entry.
As I’ve mentioned previously, I’ve reluctantly taken up running. I run 5 km three or four times a week. When I get home from my run, I often have the oddest ammonia smell in my nose. It’s not like you can smell me across the room or anything, but I’m definitely aware of it.
After noticing this two or three times, I was all ‘what gives, body? Why do you smell like Windex?” So, I asked the Internet. This seemed to be the most cogent explanation:
The smell of ammonia in sweat is common among runners. Ammonia comes from the breakdown of amino acids (the building blocks of proteins) within the body. It is made up of nitrogen and hydrogen. The hydrogen atoms are converted to glucose and used as fuel. The nitrogen is a waste product that needs to be excreted by the body, and is processed in the kidneys to form urea that is excreted in urine. If there is too much nitrogen for your kidneys to deal with, it will be excreted as ammonia in your sweat.
So how does one address this peculiar issue? From another article:
The key to avoiding that ammonia smell is to ingest sufficient carbohydrates. If you eat an ample amount of carbohydrate with every meal, then you should have plenty to fuel your exercise activity. Even people who work out on an empty stomach should have some glucose in their bloodstream upon rising – unless they subscribe to the myth that cutting out carbohydrates before bed helps you lose fat. If you find that the ammonia smell persists (even when you consume carbohydrate with every meal), try having a low glycemic carbohydrate before you workout.
A little oatmeal, a small apple, or even a piece of sprouted grain bread can provide the fuel that your body needs. Remember, your body requires fuel to burn fat! So don’t think that providing some carbs before cardio is going to eliminate the fat burning process.
And here I thought the only side effects from exercise would be looser-fitting clothes and smugness.
DarrenBarefoot.com 
Just so long as you don’t use your sweat to clean your windows, all will be OK.
Actually, there’s a lot of literature showing that the main part of losing weight is calorie restriction (four letter word ahead: diet). Exercise helps but only marginally since you will eat more to compensate for the work performed. That’s not to say that exercise shouldn’t be part of your regimen — it’s just to say that the bulk of weight reduction comes from calorie reduction.
You might find this useful/interesting
http://www.telegraph.co.uk/science/6968891/Why-expensive-trainers-could-be-worse-than-useless.html
I’ve heard that too, but I’ve definitely seen measurable results from just exercising (and no adjustment to my diet). I’m down a hole in my belt after four or five months of solid running. I could certainly have achieved more through diet + exercise, but I can’t be arsed.
Oh, very nicely done! And here’s the best part: there are two kinds of fat: subcutaneous (the roll you feel when you grab your tummy) and visceral (the fat that surrounds your internal organs). Visceral is bad stuff. Exercise helps reduce visceral fat plus exercise seems to help keep it from coming back. One other reason for your decrease in belt size is toning the tummy muscles which, previously, were relaxed and now are … well, taut is probably too strong a word … “snugger” than they were before. In any event: well done!
Nice work Darren! You could also try the opposite, and add some healthy fat to your diet instead of more carbs. From what I read today, the body will burn the fuel from carbs before it starts burning off the fat from one’s body — eating fat doesn’t make you fat, but it does provide fuel. (Who woulda thought eh?) I did find myself eating more when I started cycling 40 – 60 km/month, but when I stopped doing that I kept eating the same amount as usual. D’oh. Homeostatis is a tricky thing.