So, I’ve got a TP of 280 and a LTP at 186.
I am a bit heavy and been trying to cut down on weight, so that I can cycle better (and also for health).
My question is:
If I have a 2 hour time windown, the best for weight lost is riding at LPT? I can easily put the Neo on erg mode and get 1 or 2 hours steady at that wattage. Or would it be better trhowing some Z3 and Z4 intervals to spice things up?
Thanks
Weight loss is basically about spending more calories than you take in. So, exercise can help you do that.
That said, you can chose to target more fat burning as primary workout goal, usually at lower intensity. This differs a bit from person to person, so you should figure out your zones correctly.
At any rate, spicing things up every now an then during a long session, triggering other systems, is never bad, also to avoid boredom.
So, this lower intensity is at LTP or @ any other value?
I think you’d be best off with some Tabata-style intervals (HIIT) sandwiched with some LTP.
For example, warm-up, Tabata intervals (whatever you can handle), LTP, cooldown.
To burn the equivalent fat at low intensity you’d have to double/triple that time slot. 
Weight loss mostly happens in the kitchen, more than on the bike.
Sorry, I should have written ‘HR zones’… As commented later, you will burn calories faster at a higher intensity, but you’ll target other sources of energy storage. And yes, think before you prepare your meal in the kitchen is important, but I would think you know that. Most excess calories come from ‘snacks’ though…
target other sources of energy storage
But that doesn’t matter. They all will have to be replenished. If he mostly burns glycogen instead of only fat, that still means the next meal won’t have any excess glycogen to store as fat.
Care about the total burn, that’s what matters. Which means riding as hard as you can in the time available and still recover from.
Another factor is fun: if you like doing it and stick with it it is much more likely to work.
Building muscle is another factor, muscles use up energy even if they don’t do anything at the moment.
And with some people some form of training make them extra hungry and others don’t, that could also be a factor. I generally am less hungry when I train more and I also really prefer some healthy foods after training. As opposed to lots of sweets and snacks when just watching videos all day. Maybe the body asks for what it needs and if it doesn’t need anything your taste defaults back to comfort food? I don’t know.
So what I’d wanted to say was: Experiment! Find out what works for you and have fun.
And don’t overdo it, overtraining is a thing and injury is also more likely when you train too much. Loosing weight is best done slowly. With a TP of 280 you’re probably pretty healthy anyway.
Focus on eating real food. Focus on nutrient rather than energy content. Cut all carb drinks including all fruit juices. Regular Z2 training spiced up occasionally for fun. For Z2 focus on HR rather than power.