Science

Regardless of method, weight always boils down to a balance of calories consumed vs calories burned.

Your control of calories burned is limited - outside of physical exercise, your body does a lot of crap on its own, and finding the number of calories you passively burn on an average day is a major hurdle.

To do that, log and calculate the caloric value of everything that goes into your mouth; and your weight. If your weight is trending up, reduce your intake and keep checking. Once it stabilizes, you've got your number. If your baseline is weird, something's fucking with your metabolism - see your doctor (for real, that could be a sign of some really bad shit).

From there, you can either further decrease calories consumed by eating/drinking less, or increase calories burned by cranking up the exercise, or a combo of the two. You'll be more comfortable/satiated if you limit things like processed shit, but you can literally eat nothing but Twinkies and still lose weight if you stay within your caloric budget (you'll also be starving all the time, pissed off, and unless you're a fucking robot, give in and eat some actual food, breaking your caloric budget and thus your goals, so don't actually try the Twinkie thing, but it's 'technically' possible).

Any and every diet that actually works does so via a caloric deficit. Maybe fructose is the biggest enemy; maybe it's other sugars; or fats; but keep your caloric consumption-to-burn ratio in the negative regardless of source, and you WILL lose weight.