For example if I have a croissant for breakfast,a mcds for lunch then something for tea which in total added up to my allowance of 1400 cals a day, would I lose weight ? Or would I need to eat fruit/veg etc
Personally, I only pay attention to the calories in what I eat. I do eat more fruit and veg than I used to (which was basically none, lol), but I eat chocolate every day, and all my main meals are calorie counted ready meals. So I suppose I'm firmly in the "all calories are equal" camp! xx
Bit of both really imo - about a month ago I had a week where I stayed in calories but I also had a few packs of sweets/choc bars added in and it was a crazy week so I had a few pre-packed sandwiches and things where although I didn't gain I didn't lose anything either.
That could be a whole host of things though - so I do allow myself supposed 'bad' things, on occasion but I do try to go towards 'better' things as an actual choice
Calories are calories for losing weight, though not eating a balanced diet might not help mood levels and such. THe best thing to do is try it and if it works go for it. If it doesn't its time to reevaluate.