Losing muscle is not a requirement to lose fat. Kboxer7 has a good reply for you. The main goal is a slight caloric deficit of 10 to 20 percent. Eat healthy fats, low carb (good carbs like beans or sweat potatoes, both have NO FAT), drink plenty of water which I don't think anyone has said. Water helps you burn calories and helps keep you full and helps you to not retain water. On that note, watch you sodium intake or you will retain water. Also, try not to scale watch too much. Use the mirror more than the scale. You can totally lose fat and no muscle. High protein, about a gram per pound of lean body mass, not overall mass and make sure you are getting plenty of other macro nutrients so your body doesn't panic and you can keep all of your hormones and chemical process running smoothing inside your body. Get plenty of rest as well. You don't need to go heavy. In fact, increase your volume and you'll burn more calories! Also keep in mind that your burn double the calories you see on your machine or fitbit or whatever you have. Over the next 24 hours, you will burn the same amount you burned during cardio. Daily cardio is HUGE when you are trying to slim down. 20 to 30 mins a day and your are golden (should you be doing everything else right and longer doesn't hurt). Not sure if we are allowed to refer you to youtube but there are some great vids by Scooby1961 on the subject. Nice guy. He doesn't shout at you and gives really good information. Most rooted in science but if it is his opinion, he will be sure to tell you that. I lost 25kg following his advice and I wasn't starving... hell I was even EATING after midnight.. just no carbs that late though. Hope this helps!