Eat to Get Fit: The How-To Guide




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Eating can feel like the most complicated part of fitness.  

  • "Eat clean for 5 days, and binge for 2! It totally resets your metabolism."
  • "Cut out all gluten and sugar. Eat totally organic. You'll be set."
  • "Eat carbs in the morning. Eat protein at night."
  • "High carb, zero fat."
  • "High fat, zero carb."

Do you want to know something all of these pieces of advice have in common? You can follow all of them, and still gain fat and lose muscle. Every single one of them. I'm going to explain to you the fundamental, unbreakable principles of eating for fitness. But first, I need to define some terms. They may seem a bit boring, but trust me — there's a huge payoff for your physique once you understand these terms (many of which you've probably heard before). It starts basic, but stay with it.

Terms for Understanding Your Body

  • Calorie: A unit of energy measurement, which can calculate the energy potential in fat and sugar. "Calorie" is used to measure the potential energy in the fat and sugar in your food, as well as the fat and sugar in your body.
  • Calorie Burn: Your body's use of a "calorie." In the same way that your car burns gasoline to run its engine, your body "burns" a certain number of calories (energy) in order to perform activities — everything from unconscious bodily movements like pumping your heart and digesting your food, to conscious movements such as lifting weights and running.
  • BMR: Your "Basal Metabolic Rate" — The total calories your body burns at rest. It's different for every person, and is determined by weight, gender, and muscle mass.
  • TDEE: "Total Daily Energy Expenditure" — The total calories your body burns in an entire day — everything from getting in your car to working out.
  • Caloric Surplus: The amount of calories you eat above your TDEE, measured as a percentage. For example, if your TDEE is 2,000 calories, then if you eat 2,200 calories in a day, you are in a 10% Caloric Surplus.
    • This 10% surplus would be ideal if you were lifting weights and wanted to gain muscle or strength.
  • Caloric Deficit: The amount of calories you eat beneath your TDEE, measured as a percentage. For example, if your TDEE is 2,000 calories, then if you eat 1,600 calories in day, you are in a 20% Caloric Deficit. 
    • This 20% deficit would be ideal, if you are lifting weights, to lose fat and retain muscle.
  • Lean Muscle Mass: The total amount of mass in your body that isn't fat, measured in pounds. For example, a 200-pound person in fairly good shape may have a lean muscle mass of 180 pounds (a 10% BMI — see below)
  • BMI: "Body Mass Index" — The total percentage of your body composed of fat.
  • Bulk: A duration of time (usually 12 weeks) when you intentionally focus on building muscle or strength, while gaining as little fat as possible.
  • Dirty Bulk: When you bulk, but don't try to prevent fat gain — you simply eat what you like, and pay no concern to any fat gained in the pursuit of strength and muscle.
    • This approach makes subsequent cuts much more difficult, because they must be more intense and longer in order to lose more fat.
  • Cut: A duration of time (usually 12 weeks) when you intentionally focus on losing as much fat as possible, while maintaining as much muscle and strength as possible (which is inevitable).

Terms for Understanding Your Food

  • Protein (1 gram = 4 calories): The building blocks of muscle, measured in grams. Highly concentrated in animal products such as steak, chicken, turkey, and to a lesser degree, eggs and milk.
    • If you don't eat enough protein, your body will put your existing muscle through a process called "glycogenesis," whereby your muscle is converted to sugar for energy. If you are in a Caloric Deficit, but do not lift weights and eat a sufficient amount of protein, your body will burn your muscle for fuel. That's why most people who go on diets don't actually look more fit — they merely look like smaller versions of their former skinny-fat selves.
  • Carbohydrate (1 gram = 4 calories): The food molecule most easily converted into energy. Your body breaks carbohydrates down into sugar and utilizes it for energy very easily.
    • It's popular today to say that carbs are "bad" and fats are "good." But as a source of energy, carbohydrates provide immediate energy, whereas fat must undergo a process called "lyposis" (the breakdown of fats). Fat is a much less efficient source of energy, and a poor major source of energy for athletic performance. However, eating "zero fat" is a bad idea, because many Micronutrients (below) are "fat soluble," meaning they can only be used by the body when broken down in a fatty context.
  • Fat (1 gram = 9 calories): The food molecule intended to sustain humans for long periods without food. This food most easily makes you "feel full," and is also most easily stored as body fat. 
  • Alcohol (1 gram = 7 calories): A molecule that is metabolized by the liver and the brain which, when ingested, is metabolized before all other food consumed. So, if you eat an ice cream sandwich and drink 2 oz. of Macallan Rare Cask (no judgment here), your body will immediately digest the Macallan and store the ice cream sandwich as bodyfat.
  • Macronutrients ("Macros"): A catch-all classification which refers to the Protein, Carbohydrate, Fat, and Alcohol.
  • Micronutrients ("Micros"): A catch-all classification which refers to the vitamins and minerals in food — for example, Vitamin C, B6, K, Iron, Magnesium, etc. When people speak of "nutrition," they often have Micronutrients in mind, but proper nutrition ought to have three things in mind: (1) A certain goal dictating which nutrients (Macros and Micros) ought to be consumed, (2) Sufficient Micronutrients to achieve the goal, (3) Sufficient Macronutrients to achieve the goal.

The One Choice Every Diet Requires: Bulk Or Cut?

Before you put any of these categories to use, you have to make a decision first: Lose Fat or Build Muscle? You can only do one at a time. People will throw all kinds of stories in your face about how they gained muscle and lost fat at the same time, but that's just anecdotal evidence. Is it possible to gain muscle and lose fat at the same time? Yes, but you shouldn't build your whole workout program around that possibility. Instead, you should pursue one at a time, and take anything else you get as icing on the cake.


So, how do you know if you should bulk (gain muscle) or cut (lose fat)? If you're unhappy with the way you look in the mirror, there's a 95% chance you should cut. There are really only three reasons to begin your fitness journey with a bulk:

  1. You're super skinny. You've always had a six pack, and still have a six pack. But you really struggle to put on muscle.
  2. You're borderline anorexic. You have next to no muscle. You've been on a lot of "caloric deficits," but lack strength and vitality. 
  3. You're just going through puberty, and feel skinny-fat. I know you really want that six pack now, but trust me: You will benefit for the rest of your life from taking the time now to build muscle and strength.
    • The only exception to this is if you're overweight or obese and going through puberty, then you might want to begin with a cut. That fat loss will actually help your body restore hormonal balance to your body. You likely already have a decent amount of muscle to work with.

If you're one of these three categories, you should probably not begin with a cut, but rather a bulk. This will allow you to gain muscle, and make your subsequent cut about revealing the muscle you've built, rather than "getting skinny."


It's very simple. To bulk, or to cut, you don't need to change your workout at all. All you need to do is eat more, or eat less. Specifically:

  • To Bulk, eat a 10% Caloric Surplus for 12 weeks.
  • To Cut, eat a 20% Caloric Deficit for 12 weeks.

It really is that simple. The only thing is: adding extra cardio to your routine will increase your TDEE, and therefore allow you to eat more food while on your calorie deficit. So, for example, if you're cutting, and your regular TDEE is 2,500, that means you should eat 2,000 calories per day. But if you add an hour walk at a brisk pace 5 days a week (or 20 minutes of difficult cardio), you can add about 350 calories to your TDEE, allowing you to eat 2,350 calories — that's an extra chicken breast. Or, 35 cups of sugar-free Jell-O. Whatever your liking, it's up to you. But if you up the additional cardio, you do get to eat more (or add the extra "bite" to your fat loss).


1 Pound of fat is approximately 3,500 calories. How So, if you hit a 500 calorie deficit every day, you will lose 1 pound of fat in 1 week (500 x 7 = 3,500). If you hit a 1,000 calorie deficit every day, you will lose 2 pounds of fat in 1 week. The greater your caloric deficit, the faster you will lose fat.


However, pure starvation (that is, "fasting") has been shown to be beneficial in some studies, during a fast, you're not actually learning to build any of the habits that will sustain long-term health. The goal of maintaining a 20% deficit is not merely to learn fat, but to learn to measure how much food you're eating so that you can change your body fat and muscle composition merely by choosing to do so. Simple refraining from all food for extended periods of time not only leads to malnutrition, but also strengthens one's biological impulse to binge on food, while weakening one's metabolism severely.

A long fast (for example, a 3-day or week-long fast, which accomplishes an impressive Caloric Deficit — anywhere from 6,000 to 14,000 calories), and can be productive for weight loss in 2 circumstances: (1) if you've already had your diet and exercise under serious control for a long time, and (2) if you have an immanent event like a bodybuilding show or a trip to the beach with college friends, for which you want to appear extremely lean. Aside from these situations, fasting is a severe method that never produces long-term results.


Read this very brief Core Series introduction to calorie counting here (click here).

The One Activity Every Diet Assumes: Resistance Training

If you don't regularly perform some form of resistance training, eating a Caloric Surplus of 10% calories will only make you more fat, and eating a 20% Caloric Deficit will only make you a smaller version of your current self. 

You don't have to be an expert. Here are the Core Series articles that give you full weekly routines for resistance training — whether you're a Beginner at lifting, an Advanced lifter, or prefer an at-home bodyweight alternative.

The One Weird Rule For An Effective Diet: 1 Gram of Protein Per Pound of Bodyweight

Everybody hates this rule. It's really weird. But here's how it works: When you go to the gym, your muscles don't get bigger at the gym. When you lift weights, your body actually creates micro-tears in the muscle. It's during sleep that your body utilizes the protein you've eaten to rebuild your muscles to be even bigger, and thus adapt to the stress of lifting heavy weight.

However, if you don't eat sufficient protein, one of two things will happen. On a Bulk, if you don't eat 1 gram of protein per pound of bodyweight, you'll likely get fatter, but not stronger. On a Cut, if you don't eat 1 gram of protein per pound of bodyweight, you'll likely lose muscle during your Cut — this will result in "weight loss" (yay! ... not), but will ruin your metabolism and your physique.

Now, it's popular today to say that the bodybuilder mindset about protein is wrong — that only meatheads on steroids eat stupid amounts of protein. It's popular to say that we should only be eating 50g of protein per day. And guess what? That's true for most people. Do you know why? Because:

  1. Most people aren't lifting weights (damaging their muscles), so they don't need the protein to recover (that would be like buying building materials for a house with no land).
  2. Most people aren't in a Caloric Deficit during a Cut, so their body isn't inclined to turn to their muscles for energy — they are likely living an athletically stagnant life, slowly becoming fatter and weaker.
  3. Most people aren't trying in a Bulk, trying to hit muscle and strength goals. So, they have no need to consume materials that are intended to build muscle.
  4. If you're a stagnant person and you do consume massive amounts of protein, because you're not Cutting or Bulking, your body has no need for that macronutrient. Your body has no purpose for the protein. So, it likely increases your caloric intake unnecessarily and causes weight gain — again, if you're living a stagnant, goal-less life in regards to fitness.

Now, is there anyone who shouldn't eat 1 gram of protein per pound of bodyweight? Yes. If you are very overweight or obese, then the general guidelines of 1 gram of protein per pound of bodyweight doesn't really work. Then, you should aim for 1 gram of protein per pound of lean body mass. Your BMI (Body Mass Index) is the percent of your body composed of fat. You can calculate your lean body mass by calculating your result 

If you need help calculating your Body Fat Percentage (Sometimes called "BMI" — Body Mass Index), calculate it here:


These are the basics of eating to get fit. No lengthy scientific explanation of "carb timing" or hormone manipulation. Nothing about insulin or testosterone or cortisol. Eating for fitness is far more about how much you eat than it is about what you eat. In other words, the best diet for getting fit is highly calculated and intentional in its consumption of Macros (carbs, fats, proteins), and not built entirely on some myth about consuming the right Micros (vitamins and minerals) to put you in "fat burning mode." 

One Last Thing: Can Meal Timing Help Me Lose Weight?

When you eat during the day, and which foods you eat at which times is almost completely irrelevant to fat loss and muscle/strength gain. The only reason we should think about the timing of our meals is to help our own psychology: "What meal timing best helps me to achieve my Caloric and Macro goals?" 

Personally, I eat one big meal at the end of the day every single day. Why? Because if I'm hungry at the end of the day, I can't sleep at night. So, I eat one meal at night to ensure that I feel full when I go to bed.

However, I know many people who function much better eating 5 meals a day. It keeps them sane, and actually empowers them to achieve their Calorie and Macro goals with less psychological stress. The key is to do whatever you have to do in order to follow these basic rules of eating for fitness that we've named here: 

  1. Resistance Train
  2. Cut or Bulk (20% Caloric Deficit or 10% Surplus), but don't try to do both.
  3. 1 gram of protein per pound of bodyweight

P.S. Should I Eat Organic?

If eating organic helps you "get in the mindset" of healthy living, and you can afford it without too much stress, then by all means, eat organic. But, it won't aid your fat loss or muscle gain much at all besides the psychological payoff of "eating healthy" — which is, for many people, a strong factor. But, it is not necessary.

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