Losing fat mostly boils down to calories in, calories out. Eating less and cutting out all processed crap is a good place to start.
It's just the other end of the spectrum and their propaganda (ketofags). Although, the nutritional science of all fat = bad did turn out to be bullshit in the 2000s despite running until the late 90s. Margarine is just fat. Plant based fat, but fat regardless. Sometimes less fat than butter, which is pure butterfat, as margarine usually has water mixed in with it, so less calories. I don't think fat minimisation is specifically a bad thing, as you can usually find plenty of fat in meat and eggs already which you should always be eating, so trimming it in other areas and doubling down on salads instead is fine. I don't think the traditional idea of having your plate be 50% carb, 25% meat, 25% salad (alternatively a third each, or 10% less carb and put that into meat and salad) is a particularly bad place to start, even if it goes way deeper than that.
You might as well drink sugar water, juice is not much more than that but with some vitamins and fibre. Better to eat fruit directly. I just drink probably a few litre of tea every day since it's what I enjoy and there's zero proven ill effects from it. Alcohol is proven to be a good digestive aid, wine, cider and dark beer specifically, so a drink after a meal no more than once a day or once every other day is fine.
Other anon mentioned plain coffee. I think saying it's good for you is walking a line, the caffeine is one thing but the acidity probably harms your digestive health if in too great quantities. Just opinion.
>Also is sugarless as in no sugar or sweetener added ice cream acceptable?
I'm not a fan of non-fermented dairy products, milk doesn't contain much more than calcium, sugar and fat. In limited quantities it won't be bad, but since ice cream is a rather concentrated product you are probably just better off eating nuts and raisins if all you want is a snack.
My opinion is that nutritional science is still a bit of a mess and as it happens, it's simply everyone else's opinion and them trying to win over other people. Take everything with a grain of salt.