Low sugar (and low carbs) should really help. If you want tips (RawrGirl personally was gutted and desperate back when doing WW and barely losing anything despite 100% on plan and jogging 3 miles a day 5x a week), you can try the following. If you don't, ignore the rest of this post.
Keep your net carbs (carbs minus fiber) to around 25-30 grams and your protein to around 80 grams. That will pretty much dictate your fat and calories (your calories would be around 1000-1200 a day unless you went wild on pure fat stuff like oil, butter, mayo or full fat salad dressings). Then, start lifting weights either 3x a week total body, or 6x a week alternating with upper body one day and lower body the next. Don't worry about cardio at this point, unless it's just walking or something light that doesn't require alot of oxygen (you don't want to be panting).
This may sound like the opposite of what you've heard, but if you are keep your carbs low, you don't want to do aerobic exercise as that requires carbs. And if your body doesn't have carbs, and you do aerobic exercise, it will break down muscle to convert to carbs (less muscle = lower metabolism). Also, I'm sure you've heard anything below 1200 will also lower your metabolism, due to the dreaded "starvation mode", but if you lift weights (as heavy as you can with correct form for 12 reps, break for a minute, then repeat 2 more times), you won't lose muscle due to eating less, because you are building it right back up again. In other words, let's say eating 1000 calories forces your body to lose .25 lb of muscle a week but you lifted weights all week and built .25 of muscle. Therefore, you're body didn't lose any muscle and your metabolism stayed the same. (This is why it's important to make sure you get 80 grams of protein a day, to feed the muscle.) But since you are still eating less than your body requires, it has to pull that energy from somewhere...it's not pulling it from muscle because you're not doing cardio; it's not pulling from carbs, because you aren't eating enough carbs to create energy (just the very low amount needed for proper brain function -- about 25 grams); thus, all your body's energy to function, digest, walk from house to car, wash dishes, etc. is pulling straight from your fat stores. You are basically living off your fat (called Ketosis) even when you're sleeping. (When you first drop your carbs, it takes about 3-4 days to get into Ketosis.)
That is what RawrGirl does, and for the first time in 14 years of dieting, she finally got back into her size 8 jeans (after being a 12-14, every now and then a 10), and is now at her lowest adult weight (129, previously lowest was 138) and a never seen before size 6. No other plan ever worked for her...14 years of struggling, losing very little, giving up discouraged, gaining weight...and then she found the above plan (based on a medical study), and dropped over 25 pounds in only 4 months.
So, it's just a thought, in case you wanted to give it a go since you are trying low-sugar anyway.
