Nowadays, it still blows my mind, that with unlimited knowledge literally in the palm of our hands, so many people still adhere to some of the most ineffective protocols. Below are some of the top myths that I still see people doing to this day.

The 'Anabolic Window':

I am starting with my favorite one! Bodybuilders love taking the 2-3 hours after a training session to load up on as many carbs as possible! Hate to break it to you, I'll explain in more detail below, but if you eat too many calories, whether it be protein, carbs, or fat, in or out of the 'window', you are going to get fat. End of story.
Contrary to popular belief, you build muscle outside the 'super critical anabolic window'. MPS, muscle protein synthesis, is ignited any time an adequate amount of BCAAs flood your body (any time you eat) for around 36 hours after a resistance training session. Now, there is benefit to a small and SHORT insulin spike post workout, but this is easily done generally with a small dose of carbs with a fast digesting protein source. Even as little as 30 grams of carbs is actually sufficient despite what the popular magazines may say. So as long as you consistently eat well balanced meals containing protein on a daily basis, whether you train or not, you will recover just fine. There is no need to jam in 2500 calories in 3 hours post workout. I admittedly fell victim to this one in the beginning of my training journey. I would have my post workout shake lets say at 7am, I'd eat at 7:30, 8:30, and 10. 4 ;feedings' in a 3 hours period. Ludicrous. Now I have a shake post training, then resume normal eating protocol immediately after. Sometimes I don't even have a shake, I just eat a good meal and call it a day. Don't be like young Paul.

This will depend on your schedule. For best results, you will want to split your sessions, generally only focusing on weights or cardio each visit. That may not always be be possible however, in which case you should always do your cardio training AFTER weights.
I won't even get into specifics, but whether your goal is focusing on building muscle or losing fat, the emphasis on weight lifting is to building muscle. that is it. you don't have to train long, just train hard.

Eating less to lose more weight:

By now, a lot of us know that drastically reducing calories or simply starving yourself does not work. If that's all you had to do to get lean, we would all be walking about ripped. When you under eat, while in theory you are going to burn fat because you aren't eating much, you are actually going to end up in a highly catabolic state. Your body will actually start to break down skeletal muscle for amino acids and SLOW down your metabolism . Unless you are following a very well planned out routine competing for something such as a bodybuilding competition and have ALL of your training and nutrition perfectly mapped out, you will likely end up getting fatter. If you are under eating you could start having hormone issues which will actually make things worse. If your testosterone/estrogen/thyroid levels start to plummet, your body will be completely wrecked. This is how you can have a situation where you actually gain weight eating minimal calories. You need to FUEL your body. The more lean muscle you build via exercise the

Guessing portion sizes:

I have been counting macros and measuring my food for 15 years. I still weigh and measure everything. I never eyeball. Some people have a tendency to overeat, and those people will likely be the ones who will misjudge and take larger portions, and on the flip side if you tend to under eat like myself, you obviously

High reps are better for fat loss or sculpting:

I LOATH the word sculpting. There is building muscle, and there is losing fat. How much muscle you want to build is determined by training and diet. So is fat loss. Lifting weights builds targets muscular strength and growth. That's it. The shape of your muscles cannot be changed. Depending on your body structure, insertion points, and basically just how you are, that is what you have to work with. If you are going to do the same low intensity high volume workout in an effort to 'sculpt', while you are burning calories, if you are not actually training with enough intensity to illicit a metabolic response, you are wasting your time.

You can spot reduce fat:

Give me a break! If this were true then we actually could just do 1000 crunches a day and have a ripped stomach. How many people out there have done that? Maybe not 1000, but some ridiculous number of crunches every single day. How well did that work for you? Exactly, it didn't.
Abs are made in the kitchen.

The keys to getting in the best shape of your life are:

1. Follow a sustainable, controlled eating plan
2. Follow an intelligent training regimen
3. Repeat steps 1 and 2