ELI5 keto vs macros vs IF

It’s all in here... LINK

Keto = a diet

Keto, Paleo, Atkins etc., they're just types of diets that tell you what to eat (and not to eat) and how much of it. Some people have great success with them, others don't. Some claim they're bunk, others claim they're the Holy Grail of whatever. If you've already made up your mind that you want to pursue keto, then that's good. But don't think that there's some super special secret diet that's going to get you looking/feeling good all by itself.

Macros = protein, carbs, fats

Along with calories (kcal), these are the most important nutritional numbers you should be focusing on, on a day to day basis. Everyone's needs are different based on their goals, current body composition, and pre-existing health concerns.

IF = intermittent fasting

Similar to a diet, but more think of it more as an eating theory. You restrict yourself to a certain period of time where you're allowed to eat and then you don't eat, or consume only certain things (coffee, tea, vaginal discharge) the rest of the time. Usually people do something like 16/8 - 16 hours of no eating, then 8 hours where you eat what you want (provided it fits your diet and macros as discussed above). If you're a smart dude, you'll realize that less time to eat means you are more likely to eat less food - sorry to ruin the magic. People claim there are other benefits...increased testosterone, elevated fat burning, sharper mental focus, bigger penis etc. You can pull studies backing up and countering any of those claims except for the penis one. There's really no universally agreed upon conclusion.

The advice about using IIFYM or some other macro calculator and MyFitnessPal is excellent. Once you figure that out and tell us more about your goals and where you're starting, we can guide you better. If you're really autistic you can get a food scale and weigh everything you eat. Generally though...

Let's say your MAINTENANCE calories are 2000. If you ate a perfect 2000 calories every day, your weight would largely stay the same.

Wanna lose weight? Eat at a 10% caloric deficit - 1800 calories
Wanna lose weight faster? Eat 500 calories below maintenance - 1500 calories
Wanna lose weight even faster? Starve yourself - 0 calories

Wanna gain weight? Eat at a 10% caloric surplus - 2200 calories
Wanna gain weight faster? Eat 500 calories above maintenance - 2500 calories
Wanna gain weight even faster? YOLO eat whatever you want - infinite calories

In all seriousness, if you're the average out of shape dude in his 30s or 40s you don't NEED a special diet or all that other complicated shite to get started. Just eat less and move more. Eat like an adult and do something active until you're sweating and breathing hard. See where that gets you after 6 weeks then look into implementing the other stuff.

Figure out what you can stick to.

All can work, but they're vastly different in terms of what you eat and how. The best one for you will be the one you can consistently do.

Macros + workout program = change your body. Adjusting those inputs leads to different outputs.

Keto is an anti-epilepsy diet that tends to correlate to an improvement in body composition due to the change in macros.

IF is a timed-eating lifestyle theory that appears to have intrinsic health benefits. It also correlates to an improvement in body composition, likely due primarily to a change in macros (i.e. eating less total).

I'm a big proponent of IF. I think it's a beneficial lifestyle decision for literally everyone.

Personally I wouldn't use keto as a body changing method. I would only use it if I was an epileptic.