I use web data, and weigh everything with a small counter-top scale. I also use the web to estimate exercise calories. Then I use an equation that considers my resting calorie needs and will show me how mch I can eat and still have a 500 calorie deficit.

Because I've been afraid of cheating, I usually estimate the numbers to show I'm eating more than I actually am. But now I think it's making me too tired.

Maybe I should try like Stacy said and eat a little while on the bike, and a little less off the bike.

But it seems silly to eat something on the bike if it's only a 90 minute ride!