the tomato technique, yeah i works wonders, unless you pay attention somewhere else. Also give yourself a proper reward at the end, that boosts confidence an rewires the brain also. Overstressing is actually worse than being overweight, in fact many people gain weight because they are stressed, which basically gets the body to produce cortisol and store fat.
So yeah sugar is a killer too, I started by drinking tea, then a few years later basically, I stopped drinking sugar with my coffee and now I can't even think of putting it anywhere, I basically do well with fruits and well winters are tough, I still eat sweets from time to time, but it's always disheartening seeing cheap oils and soy and something else, basically manufacturers care to satisfy regulators and get as low as possible, so basically one sweet costs some cents, the packaging costs a few more cents and in the end you get to pay for the shipping, the manufacturing, the raw materials, the distribution and the retailer :D and all the associated costs from the government and the draining of energy for the production.
I do wonder if when people were cooking at home all this was pure fantasy. I don't get the rush for more and more, It's never enough. I think it creates more problems than it solves.