yeh i weigh myself daily which is a no-no apparently but i don't care. I know weight can fluctuate from day to day but who cares.
sticking to it without grabbing a burger is the hardest part with my type of low carb, low fat diet, but there are options. For example, if you choose subway, go for the roast chicken, and a low fat sauce like honey mustard, which is 0.3g per 6 inch sandwich compared with say mayo which is about 5g per 6 inch, or southwest sauce which is about 9g per 6 inch. It makes a big difference. Also at maccas there is a seared classic chicken burger which is actually pretty nice and only 12g from memory. It's quite filling. Just don't get chips or anything with it. It gives you the illusion of eating pretty badly but not, and tides you over for a while.
Joke of it is, as i said earlier i didn't even become overweight from eating junk, just too much home cooking and a dodgy med. But there are ways of breaking the monotony if you choose the occasional junk-meal properly. Kebabs can be healthy too, with the right ingredients.
If you want to get an idea of the nutritional value of anything you want to eat, to plan your daily food intake, try
www.calorieking.com.au <-- pretty good site. You don't have to join, there's a search form on the right side of the front page where you can quick search various ingredients or pre-made foods.