Okay so I may be able to help as a complete newbie here but someone maybe 5 weeks farther on from you. I was/am that couch potato (190cm tall, 117kgs fat) and yet am starting become someone who loves being out there. I've tried everything in the past; slimfast shakes, 5:2 diet, juicing, Russian airforce diet (so many boiled eggs it hurt), ketosis the lot. What has worked for me is not a fad or a shake or a 'diet' it's a shift in mindset. In 6 weeks i'm down to 105kgs (still 190cm tall). Here's what's been working for me:
The No CRAP diet. (It's an acronym) Low Carbs (less than 100g a day) really read that package. Have a real life protein (meat/egg etc) with every meal as it makes you feel fuller for longer. Use protein a lot! I now snack on spicy chicken chunks or smoked sausage slices (high in fat though so be careful of going crazy). More important than watching the Carbs though is the 'of which sugars' line which in the UK tells you what amount of the carbs are sugar. This leads on to the 'R' which is:
No Refined Sugar. I used to sleep loads in the day basically because i'd give myself a sugar coma at lunch and be exhausted at 4pm. I've been so much more energetic once I got passed my craving for it. I promise you there is a point where you stop thinking about wanting to cheat or binge. Cut it out of your diet and after a while your body will not want it as much.
No Alcohol (Well much less. There's so much sugar in a lot of it. If you want it go for Gin and tonic, clear spirits etc with Diet Coke.)
No Processed food. Make sure you know what you're putting in by making it yourself. Do you know what's in the packs you're eating?
In the past I just cut out things from my life but found i always craved them and always gave in. Lifesaving swaps this time: Chocolate swapped for DARK chocolate (75 - 80% cocoa). Really savour a cube rather than bashing a whole bar. Roll it round your mouth, really taste it. Take in its subtleties and flavours.
Sweet potato (yam?) instead of normal potatos. Cut those bad boys thin, dribble them in oil and season really well. Oven bake until like crisps (chips?) and go mad on them.
Diet Coke/drinks instead of other non - diet drink. I know they're full of crap but for that sweet tooth hit it's good and if weight loss is your aim realise how much sugar is in some of the liquids you drink.
Pasta for... well no swap found yet but I have been cooking and eating a lot of bacon and egg for breakfast (with mushrooms and tomatos) and well Bacon can be substituted for anything so that's my swap.
Brown rice instead of white rice. Brown rice still sort of sucks but it's better for you and if i add a lot of bacon i can kind of just taste bacon.
So other tips: KEEP A FOOD DIARY. By writing down anything in your book before you eat it you have another level of accountability. Don't lie to yourself. If you're not losing weight you're taking in more calories than you are using. It's just science. It's not your build, it's not your metabolism it's that your are cheating somewhere. Also find someone who terrifies you to be your weighing in buddy. Weigh in at the same time of day on the same surface in the same clothes and have that person know what weight you have lost. If they terrify you and haunt your dreams all the better as it will stop you eating crud.
Other than that. Just get up. I made excuses all the time. 'My kids, my work, my stress, my tiredness, my failures before etc.' Your couch is robbing you of the person you could be. Get up, lace up your shoes and start walking trying to hit 10,000 steps a day. Get a phone that counts for you and check it at 12pm each day. Adjust your afternoon activity level to make sure you hit the target. Find an exercise you love (i love swimming and tennis) and do them as it feels more like fun than work.
I've got a long way to go and am afraid of relapsing but this time it feels different and I'm looking forward to a longer life, doing more with my kids and basically being a sexy hot piece of meat this summer not afraid to take my shirt off on the beach for the first time. Ever.