I don’t feel that it matters how much fat is in your diet, as long as what you’re eating is satisfying you. Sometimes the low fat products have about the same calorie count as the full fat, because of the added sugars as Janet said. But sometimes the full fat product has so many extra calories that it’s hard to fit into your daily 800.
For that reason I’ve been using skim milk in my two cups of coffee a day. I’d much prefer full fat, but then I’d have to cut back on something else. I really enjoy full fat Greek yoghurt, but again, I have to read the labels very carefully to try to keep the calorie count down as much as possible.
If your carb count is acceptable, and you’re keeping within your calorie limit, I’d go with whatever you enjoy. If you don’t like the food, you won’t stick to it long term.