Keto diet macros: Redefining protein, fat, and carbs on keto

From the desk of
Luis Villaseñor
ScienceKeto diet macros: Redefining protein, fat, and carbs on keto

There’s a lot of prominent misinformed advice on keto diet macros, and it’s hindering people’s body recomposition goals. The first issue? Most advice centers around a classical ketogenic diet (CKD), which was used to help treat childhood epilepsy in the 1920s. This version of the ketogenic diet is low in protein, extremely low in carbs, and very high in fat, accounting for about 90% of one’s calorie intake.

While the CKD increases ketones into the therapeutic range, it’s not the best for lean mass and overall health. The point is: If you want to lose body fat and gain or maintain muscle, focusing on dietary fat isn’t an optimal strategy. What you really need is protein.

This shift in keto macros (away from fat and towards protein) lies at the core of my macro philosophy. I have seen it help thousands of people achieve fat loss, improve their body composition, and reach other health goals on keto. I’m not against fat, of course. With carbs mostly out of the picture, fat must account for a good chunk of your caloric load. But your focus should be protein, the king of macros. 

In a sentence: Limit carbs, make protein a goal, and use fat as a lever—an adjustable calorie switch to increase or decrease depending on your current goals. This article will cover my philosophy about macros on the ketogenic diet in depth. Let’s start with the fundamentals.

What Are Macros?

Macros is short for macronutrients. The three main macronutrients—carbohydrates, protein, and fat—provide the calories (stored energy) needed to produce the actual usable energy, or ATP, that powers every one of your cells (1).

Alcohol can also be seen as a macro, as it yields calories and ATP. But it doesn’t have any real functions in your body, so we’re going to leave it aside for now. Ketones can also be seen as another macro, for the same reasons as alcohol. They’re a byproduct of fat metabolization, have calories, and produce ATP as well.

Each macro contains a set number of calories per gram, a point we’ll return to later:

    • Carbohydrate: 4 calories per gram
    • Protein: 4 calories per gram
    • Fat: 9 calories per gram
  • (Alcohol: 7 calories per gram)
  • (Ketones: about 4 calories per gram)

Macronutrients are called macro-nutrients because our bodies require them in large (or macro) amounts. On the other side of the coin are micronutrients like vitamins and minerals. These nutrients are essential for human health, but required in smaller amounts.

Food contains a mix of macronutrients and micronutrients. Whole foods like beef, spinach, and eggs offer a wide spectrum of nutrients, while processed foods (unless fortified) typically do not. However, in an effort to prevent population-wide vitamin and mineral deficiencies, the US government mandates the fortification of cereal, bread, and many other processed foods.

Let’s get back to macros, now. Of the three, carbs are the only macronutrients that do not have to come through diet. If you don’t eat carbs, your body will still produce glucose—a sugar that powers your brain and other cells—through a process called gluconeogenesis.

Unlike carbs, protein is definitely not optional. Your body cannot really store protein, and so it requires amino acids (the building blocks of protein) to be consumed on a daily basis. This helps your body to build, maintain, and repair muscle, bone, skin, hair, and organs, and to synthesize both enzymes and hormones. Your body is a protein-built machine.

Protein’s main drawback?* It’s not a great source of usable energy. In other words, it’s not easily converted into ATP. For one, a lot of calories are wasted as heat. And two, it’s metabolically expensive for your body to obtain calories from it—so it can be difficult to keep up with your body’s demands. *Note that this “drawback” can also be considered an advantage, as protein being an inefficient energy source means you hold onto less calories from protein—thus helping with fat loss.

Fat, on the other hand, is a great source of energy that can be stored in nearly unlimited quantities. Fat also helps you build cell membranes, absorb vitamins, synthesize hormones and support brain function.

Obviously, most of us don’t want to store fat in unlimited quantities. We want to store just enough, and access that body fat when needed.

But the modern diet doesn’t promote that situation.

The Problem With Modern Diets

There are two main ways to supply reliable energy to your body:

  1. By consuming dietary carbohydrates
  2. By consuming dietary fat and burning body fat

The problem with the modern diet is that it promotes door #1 (carbs) in an extreme excess.

When a high proportion of your calories come from carbs, you block the pathways needed to access stored body fat. Specifically, high-carb diets increase the hormone insulin, which tells your body to “shuttle all nutrients and energy in the cells”. So, while insulin is high, fat burning is minimized.

And if you take a look at most people’s diets, you will find that they’re very high in overly-processed carbs AND also quite high in fat (especially cheap, highly processed oils). Picture the snack aisle of a supermarket or the fast food menu: pizza, donuts, TV Dinners… an abundance of easily absorbed energy sources.

That’s why the modern diet is a double-edged sword:

  1. The high-fat foods are stored as body fat because there is an excess of easily-broken down carbs available for energy.
  2. The excess carbs (and therefore high insulin) impede the burning of that stored body fat.

No amount of exercise (unless you train like Michael Phelps) will burn those calories, contrary to a lot of claims (3).

Sure, you’ll burn some fat during exercise. Even if you eat high-carb. But at rest, you’ll be mostly reliant on carbs (aka glucose) for energy.

If you’re trying to lose fat and gain muscle, this isn’t ideal. You want to utilize body fat for energy whenever possible. This won’t happen if you’re constantly pumping up your blood sugar (and, as a result, your insulin levels) with carbs.

And that’s where carb restriction comes in.

How The Keto Diet Works

On a ketogenic diet, you get most of your energy from door #2: Body fat and dietary fat.

You open door #2 by following the #1 rule of keto: Keep carbs low.

Keeping carbs low…

  • Depletes glycogen (stored glucose) in your liver
  • Causes insulin to fall, which helps you access stored body fat
  • Increases glucagon, a hormone that prevents blood sugar from falling too low

The sum of these changes (especially the drop in insulin) allows you to burn more body fat throughout the day. And when you burn fat for energy in a carb-restricted and low-insulin state, you produce ketones.

Ketones, like fatty acids, are a functional energy source (we talked about them briefly before—they produce 4 kcals/gram). You may know that the main source of energy for your brain is glucose, and that it requires around 100g of it per day.

The problem with getting your energy from just fat is that fatty acids cannot cross the blood-brain barrier. This is where Ketones come in. Unlike fatty acids, ketones can cross the blood-brain barrier as brain fuel. Basically, ketones reduce your brain’s reliance on glucose.

Again, to burn fat and make ketones, all you need to do is restrict carbs. Both intermittent fasting and low-carb diets will get you there.

But what about the other macros?

Dialing In Your Keto Macros

If you remember one thing from this article, remember this: Protein is a goal, carbs are a limit, and fat is a lever.

Protein Is A Goal

What’s the biggest mistake we see clients making on keto? Easy: Not eating enough protein.

Protein is the stuff of life. The amino acids from protein structure every tissue in your body—muscle, bone, connective tissue, organs, you name it.

Protein is also the most satiating macronutrient. The fuller you feel, the less likely you are to overeat. Unsurprisingly, the research on high-protein diets for weight loss is fairly compelling.

We recommend eating at least 0.8 grams of daily protein per pound of lean body mass (LBM) on normal days, and around 1 gram per pound LBM on active days (you can of course, eat more if you want to). Depending on your size and body composition, this usually lies between 100-180 grams of protein per day.

Won’t all that protein kick you out of ketosis? Unlikely. Multiple studies have shown that high protein keto diets are perfectly compatible with fat loss and muscle maintenance[*][*].

Carbs Are A Limit

Limiting carbohydrate intake keeps blood sugar and insulin levels low, which in turn allows you to access body fat as a main energy source. This is the key to ketosis.

Keeping carbs low isn’t always easy. The modern Western diet is high-carb by design, and most packaged foods should be avoided.

A good strategy while grocery shopping is to stick to the periphery, or outer bounds, of the supermarket. You’re looking for meats, fish, eggs, and non-starchy veggies. In other words, you’re looking for low-carb whole foods.

We recommend starting with 30 grams net carbs per day. (Net carbs = total carbs – fiber – sugar alcohols). Restricting carbs to this level will facilitate your fat-adaptation.

Fat Is A Lever

Fat is a crucial energy source. The issue with fat, however, is that it contains 9 calories per gram.

That means that, in terms of calories, 40 grams of fat is the same as 90 grams of protein! This level of energy density makes it easy to overeat.

If your goal is fat loss, you’ll want to avoid eating large amounts of fat. For those looking to lose weight, we recommend starting with 50 grams per day.

If you’re looking to gain muscle, fat can go higher as your caloric needs rise. That’s why we say that fat is a lever. You lever it up or down to suit your goals.

In general, however, most people have levered up fat too high on keto. For better results, replace that fat with protein.

Why We Don’t Recommend A High-Fat Keto Diet

A high-fat keto diet is more or less dogma these days. And even though that’s great for a therapeutic approach, most people who follow a Keto Diet these days are doing so for fat loss. Understand the following:

  • Protein is more satiating than fat. A high-protein diet is better suited to weight loss or maintenance goals, and also has a high TEF (Thermic Effect of Food).
  • Fat calories often come at the expense of protein calories. And if you don’t get enough protein, you’ll lose your beautiful muscles.
  • Fat has ZERO TEF. Of all the macronutrients, dietary fat is the most easily stored as body fat.
  • Fat is largely devoid of vitamins and minerals. If you’re getting 70-80% of your calories from fat, micronutrient deficiency may be a real concern.

To be clear, we’re not saying to avoid fat on keto. Carbs are what you should minimize. But we are urging you to prioritize protein goals over fat.

Again: focus on protein like a goal, keep carbs low with a limit, and manage fat intake like a lever (but don’t over-do it).

Macros Are Like Money

We’ll leave you with an analogy.

Macros and calories are like money. Invest them to yield the best results.

Your macros and calories are your budget. How will you spend them?

Investing in carbs makes it difficult to access and burn body fat. So you want to limit that spending.

Investing some in fat is okay, but be mindful here. Fat is easy to overdo, and often displaces more nutrient-dense and satiating protein-rich foods. Plus, investing in fat when you already have lots of fat stored in your body is a bad use of your budget – prioritize fat burning, but from your own fat stores first.

Save a big wad of calorie cash for protein. High-protein whole foods fill you up, keep you strong, help you burn extra calories, and help you reach your body composition goals.

If you’re not sure how many calories you’re consuming, use an app like Cronometer to figure this out. Don’t get too bent out of shape obsessively tracking macros. At the end of the day, dietary decisions are about bettering the way you look, feel, and perform – not numbers on the macros calculators.

Intuitively eating protein-rich whole foods and low-carb vegetables, while leveraging fat as you need to will be your best friend. Once you start eating this way, you’ll never want to go back.

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