Since I see stuff pop up like this all the time, I may as well write up how I went about cutting from 300+ to 215 lbs and subsequently putting on significant muscle mass and strength while keeping the weight off.

Step 1: identify why you want to lose weight.

The biggest reason people fail to lose weight is because they never really wanted to lose weight to begin with. What do I mean by this? A lot of people jump into weight loss without ever clearly articulating an overarching strong motivator for weight loss. The result is that when these people are confronted with hardship they are quick to give up because there is nothing driving them. Sit down and ask yourself why you want to be a different person. The more subjective the driver, the better. My reason was that I wanted to get a girlfriend and I knew I could never do this being very obese. Other good goals might be "I want to be around to walk my daughter down the aisle"; "I want to take my shirt off and have people be amazed"; "I want to live to see my grandchildren grow up"; "I want senpai to notice me" etc. Bad goals include "I want to be in good health"; "I want my cholesterol to lower by 20 points"; "I want to weigh X" and other proxies that no one really cares about (although these make excellent iterative goals to judge progress by).

Once you have identified this goal, write it down 10 times on paper every morning and repeat it to yourself in your head throughout the day. This will help you internalize it and dissuade you from breaking adherence when you are tempted. This may seem useless, but if you can't even write something down ten times every morning then how are you going to go about changing multiple systems in your life?

Step 2: pick your weapon

Pretty much any validated diet will work if you actually follow it to the letter. Zone, Atkins/keto, paelo, low fat, calorie counting, IIFYM and more are all viable choices. Some are easier to adhere to than others given your lifestyle. For example if you eat our a lot then keto is easier than calorie counting because you don't really have access to the ingredients to tabulate them. Don't get hung up on what is "optimal". The best diet plan is the one you are going to actually follow. Also, remember that you want to pick something that you will be able to follow forever. People incorrectly think of weight management as a discrete process that gets abandoned once you hit your goal. This is incorrect. You will need to actively manage your weight your entire life.

Step 3: measure

You can't evaluate what you can't measure. Get a scale and record your weight each day. Get MyFitnessPal and record your meals.

Step 4: design your systems

The second biggest reason people fail at dieting is because they don't have any systems. They therefore flail around and eventually give up because they aren't making progress. Let's say you want to do keto. Design 3-4 meals in my fitness pal that you will enjoy that fit your meal plan. Eat one of those variants every day. This makes meal planning simple, cheap, and easy. The less cognitive overhead you have to exert to adhere to the program, the easier adherence will be. I would also recommend getting a standard time to do meal prep, clean up, record your bodyweight etc. Checklists can be very helpful here as can tracking the number of days you are adherent.

Furthermore, set up your environment for success. Don't go out to eat with people until you are confident in your ability to say no to bad choices. Don't keep shitty food around in your home etc. Willpower is overrated, make non-adherence difficult. Your goal should be to construct a system where you have to use the least amount of willpower possible to adhere.

I would definitely recommend setting up social adherence aids like telling your friends you are doing a diet so they can call you on it when you don't perform well or feel like giving up, putting money on the line, creating a X days adherent ticker etc. This will create more pressure on yourself to adhere

Step 5: plan for contingencies

You will inevitably find yourself in an edge case situation where dieting will be harder. It's important to think about common edge cases you may encounter and develop plans to deal with them.

Common ones for me were things like:

I'm stuck late at work

- I had protein bars and powder in my desk

- I had meal templates in my fitness for common meals at restaurants near my workplace

I'm stuck somewhere in the middle of nowhere

- I had protein bars and snacks in my backpack

- I knew fast food meal options that fit my diet plan

I have to go to an event where bad food will be served

- I ate beforehand or afterwards and told people I am dieting. Not only were they cool with it but they were very supportive

I'm going out drinking

- I knew how many calories and carbs were in common beers and liquor by heart.

- I purged my house of bad food so if I was drunk I couldn't eat it

Eventually you will encounter a situation you haven't planned for, which is where your overarching goal, social pressure, habits, and willpower will kick in and save you if you let them. Power through.

Step 6: move your ass

Do some exercise. It doesn't really matter what. Similar to diet plan optimization, people often ask me what the "best" exercise is. My answer is always the one you will do. For me that is powerlifting. For other people it could be basketball, badminton, running, walking, bodybuilding, cycling, swimming, tree climbing whatever. As long as you do it regularly you will find success. I find it useful to also record progress in these endeavors as it helps adherence and also serves as an added motivator to diet.

The one thing I would say is be reasonable. If you have never run before don't so something like interval training. You will fucking die and give up. Start with jogging and build up to that etc.

Step 7: execute!

You have your plans now go out and execute. The key to dieting success is adherence adherence adherence. NO CHEAT DAYS, NO CHEAT MEALS, NO EXCUSES OR SPECIAL OCASSIONS. For my birthday I would always turn down cake and eating out and instead diet extra hard as recognition of my hard work. My weight loss was my present, I didn't need more. Remember that if people try to exert social pressure on you to break your diet, it's because they are weak or they are not your friends. Your real loved ones will understand and support you when you turn down their birthday cake or invitation to go eat bad food. In a moment of weakness during my birthday I went to order a craft beer only to have my good friend tell me to stop fucking up. That's a true friend :D

The big takeaway here is that this stuff really isn't that hard and the planning doesn't take much time. I literally did an hour of planning before I embarked on my diet after someone told me "you should try Atkins" and iterated as I went.

Also, once you develop a set of reasonable systems, you won't need to worry about putting weight on because you can just modify your systems for maintenance instead of weight loss. A big reason why people put weight back on is because they treat weight management as dieting. To see how stupid this is, imagine you are trying to achieve financial stability and you start by saying "I'm going to slash my expenses to the bone and then when I'm debt free I can go back to normal". It's immediately obvious that this plan will lead to long term or even short term failure and yet people typically approach their weight this way. Please don't be that guy or girl. Also if you need help or are confused please feel free to ping me.