the short answer is yes. they are. i've got an interest in nutrition and i'm a bit of a gym rat. don't get me wrong, my diet is appalling but that's only because of the hours i work - i don't have time to eat healthily lol.
the main things to watch out for are saturated fats and salt. take aways are high in both. you can eat as much as you like if you're doing the exercise to work it off. i exercise a lot, and my job is quite physically demanding so i can eat a lot and i'm still losing weight (i'm around the 80kg mark now, i was around the 87kg mark when i started this job 6 months ago).
i once worked out that because of my height, muscle mass, the job i do etc. i need around 3000 calories on a training day just to break even. the recommended daily allowance is 2000kcal.
i'm slightly different to most ppl in that i'm actively looking to put on weight. i'm about 6ft 2" and i think i'm skinny. i went on a weight training programme and got my weight up from around 70kg to 85kg in about a year. i used to have a McDonald's 3 times a week because i NEEDED the extra fat and calories - but i noted that i was putting on fat as well. i stopped eating the chips and replaced it with a healthier source of carbohydrate and problem solved. little changes in diet can make big changes in your appearance.
HOWEVER polyunsaturated fats are good for you. they lower your cholesterol and reduce your chance of heart disease. monounsaturated fats are indifferent. neither of them will increase your body fat, unless you're eating stupid amounts. peanuts, walnuts etc. are loaded with "good" fats. it's the saturated fats to watch out for and sadly take aways are loaded with them.