NOTE: This is part of a running series of Question and Answer posts answering questions from readers and redditors.
Q: I know the purpose of a ‘cut’ is to increase one’s muscle definition by shedding body fat. How does this differ from what the rest of the world knows as ‘dieting’?
A: Simply – It doesn’t. What you are thinking of as dieting is the same thing as cutting. Reducing caloric intake to shed fat. Dieting is a more general term, IMHO, as the term diet simply means the sum of food consumed by an organism, irrespective of the organism’s goals. Cutting, bulking, and recomping are diets related to specific goals. Cutting is the act of trying to shed body fat while maintaining lean mass as much as possible, bulking is increasing lean mass as much as possible while hopefully increasing fat mass as little as possible, and recomping is attempting to increase lean mass while simultaneously reducing fat mass.

Q: I thought that reducing caloric intake makes the body try to resist shedding fat reserves because it thinks you’re in the midst of a famine, and that lifting fasted was supposed to be a bad idea because there’s nothing to run on. Is this wrong?
A: What you are thinking of is what diet ‘gurus’ call ‘starvation mode’, and it comes from the Minnesota Starvation Experiment. Basically, when subjected to actual starvation, the body takes steps to protect itself by reducing energy levels and generally making you feel crummy so you won’t move around as much. It also alters a number of hormonal levels and genuinely slows down your metabolism a bit.

Here’s the thing, though: It’s almost impossible to get to a place where your body stops burning fat on a deficit. Your metabolism might decrease by 10%, but if your deficit is over 10%, you are still going to lose weight. So it’s really not that big of a deal to start with, and you will probably never see it. And if you do see some amount of metabolism slowdown from sensibly cutting/dieting, oh well. How much your body fights back by reducing metabolism is largely individual and preordained. Since there’s nothing you can do about it, you are best served by not worrying about it and just adjusting your diet as necessary to meet your goals.

Q: Is there something different about dieting for lifters? After a lifetime of obsession over caloric intake, I get to Fitocracy and suddenly find everyone worrying about whether they are eating enough or not.
A: There’s not really anything different about dieting for the two groups in general, but the goals for folks on Fitocracy are generally more complex than the average ‘dieter’. Most folk who are on a diet have the simple goal of losing weight. Now, in their mind, they generally want to look good, but the goal they set for themselves is to hit a certain body weight, not a certain body fat and lean mass level.
Since the average dieter is trying to just lose weight, even losing lean mass is acceptable, and they usually reach their goals by losing large quantities of lean mass. The result of this is that they often end up looking worse (and sometimes being more unhealthy) than when they started. 

On the other hand, a fitness enthusiast generally has some idea about the difference in lean and fat mass and is actively trying to increase or at least maintain lean mass while reducing fat. This leads to a very different diet.

See, one of the tricks to gaining and or maintaining muscle while losing fat is that your body has to have enough protein to do so. The problem is, you have to get enough protein to grow muscle in a small enough number of calories to lose fat. So, to give you an example:

Say a person weighs 200 lbs at 20% BF and wants to lose weight while maintaining or increasing muscle. They have 160 lbs of lean mass and 40 lbs of fat. To maintain, the absolute minimum protein they need is 160g/day, but to grow, they ideally need 200-240g/day.

However, they also want to lose fat at a rate of 2lbs per week, so they need to create a caloric deficit of roughly 7000 calories per week, which works out to 1000 calories per day. So, if their average Total Daily Energy Expenditure is 3000 calories, they need to drop that to 2000 calories.

So, their basic diet is 2000 calories per day with 240g of protein. Protein is 4 calories per gram, so 240×4=960 calories just from protein (and that would be pure). However, it’s pretty much impossible to get pure protein, so let’s say they go with an incredibly lean choice like skinless chicken breast and don’t screw it up with sauces or breading.

4oz of boneless, skinless, raw chicken breast has the following macros:
Calories: 129, Total Fat: 1.46g, Total Carbs: 0g, Protein: 27.25g

So, to get all of his protein, this person needs to eat 240/27.25 chicken breasts, or basically 9, 4oz breasts. 9×4 is 36, so this person needs to eat a little over 2 lbs of bland, no sauce, no breading chicken breast every day.

But wait, there’s more!

The chicken breast totaled up to 1161 calories, which leaves him 839 calories in the day. Now, your first thought might be to liven up that chicken with some BBQ sauce or something, but that wouldn’t be very balanced, and would leave our would-be bodybuilder feeling like poop (and probably having some difficulty in that regard as well, due to lack of fiber). Sooooo…Let’s get some healthy stuff in there to balance his diet.

Basically, we want some vegetables (preferably green), a fruit or two, something with insoluble fiber for digestion (soluble is easy to get from supplements, but insoluble is not), and something dairy for the calcium, vitamin D, and other goodness.

Let’s start with a Salad. Sans dressing, cheese, bacon bits, etc (just the greens), a salad is roughly 50 calories for a plate (2 cups).

Next, let’s knock the insoluble fiber out, since it’s hard to come by. General Mills Fiber One breakfast cereal actually contains 14g of Fiber per half cup serving, a lot of it insoluble, so 1 cup of that should pretty much knock out our fiber needs for 120 calories. Also, that gives us the chance to knock out our dairy by including a cup of milk. I prefer (and would suggest) whole milk for a lot of reasons, so that’s 146 calories. So, so far, we are at:
36 oz of chicken: 1161
Salad: 50
Cereal: 120
Milk:146
TOTAL: 1477
REMAINING: 533

Toss in an apple for fruit (100 calories), and you’ve got everything more or less covered for 1577 calories, which means he can use the remaining 433 calories for sauces, salad dressing, or pop tarts (exactly 2). But overall, in a day, EVERY day, he has to eat:
36 oz of chicken
2 cups of salad
1 cup of cereal
1 cup of milk
1 apple

For some people, this can be rough. As a former fat boy, I have no issue at all with this, but I’ve found from experience that women and skinny-fat guys, in particular, seem to have a real hard time eating all of that meat.