What Are Macronutrients? A Beginner's Guide to Keto Ratios
What Are Macronutrients?
Macronutrients are proteins, fats, and carbohydrates.
Every diet involves cutting back on one macronutrient and leaning more heavily on another. Traditional diets tend to restrict fat, while keto takes the opposite approach and restricts carbs instead.
That restriction is what allows your body to start using fat as its primary fuel source. The core of keto comes down to keeping net carbs around 25–30 g a day while increasing fat intake. A low-carb, high-fat approach like this pushes your body into ketosis, a state where it burns fat for energy instead of relying on glucose from carbohydrates. Since carbs make up only about 5% of your daily calories on keto, the rest comes from healthy fats and a moderate amount of protein.
On the ketogenic diet, your daily calories break down roughly like this:
Depending on your goals and how your body responds, you may be able to go up to 50 g of total carbs a day. Just be careful, it's easier than you'd think to go over that without realizing it.
Calculating Your Macros
This step can feel a little overwhelming at first, but it's honestly one of the simpler parts of starting keto. Here's how to break it down:
If you're in weight-loss mode, it helps to think about your macros over the course of a month rather than day to day. It's completely normal to eat a bit more than your target calories in the beginning, and most calculators let you adjust your deficit as you go. Starting with a smaller deficit is usually the smarter move. As your body adjusts to ketosis, give yourself enough fat to keep carb cravings in check. Trying to adapt to a high-fat diet while also cutting calories aggressively is a recipe for burnout, don't make that mistake during the adjustment period. Once you're a month or so in and settled into ketosis, feel free to increase your deficit in line with your weight loss goals.
Once you've calculated your calories and macros, the next essential step is tracking them daily. A good app makes this far easier. Two popular options:
Log everything you eat, even the small stuff, and get in the habit of weighing food in its raw form. It might feel tedious at first, but it genuinely pays off. Not only will it give you a clear, accurate picture of your intake, it'll also help you troubleshoot quickly if you notice you're not losing weight or seem to have slipped out of ketosis.
Net Carbs vs. Total Carbs
Net carbs, sometimes called "effective carbs," are simply total carbohydrates minus fiber. To keep things simple, a good rule of thumb is:
Aim for 20–30 g of net carbs, or 30–50 g of total carbs, per day.
If your target is 20 g of net carbs a day, avocado might seem like a questionable choice at first glance, since an average avocado has around 9 g of total carbs. But look closer: that same avocado also has about 7 g of fiber, which brings the net carb count down to just 2 g. If your daily limit is 20 g of net carbs, that avocado fits in easily.
This is exactly why net carbs matter more than total carbs when you're tracking. Most apps, including Fatsecret, let you add a dedicated "net carbs" column to make this easier. And don't forget: portion size changes everything. That 2 g figure is for an average-sized avocado, so a larger one means adjusting the math accordingly. When in doubt, weigh it.
How Much Should You Actually Eat?
When starting a low-carb diet, it's tempting to assume eating less across the board will speed things along. This is one of the most common beginner mistakes, cutting carbs, fats, and protein all at once. Rather than helping, this tends to confuse your body and stall your progress.
Deprive your body of the nutrients it needs, and it shifts into something close to starvation mode, where it stops functioning at its best.
Cutting protein too aggressively, in particular, leads to muscle loss over time, your body will start breaking down its own muscle tissue for fuel. Even on days when you feel full, make sure you're still hitting your full calorie target. If you're falling short, fat bombs, mashed avocado, or a splash of butter in your morning coffee are easy ways to close the gap. Consistently meeting your daily calories supports better weight loss and how you feel day to day.
It's also worth keeping your kitchen well-stocked with fat, especially in the first few weeks. When hunger hits and you're tempted to just push through it, reach for fat instead. Hitting your daily fat target helps keep you satisfied and curbs unnecessary hunger. And once you're in ketosis, fat becomes your body's main energy source, so the more of it you're eating, the more steady energy you'll have throughout the day.
Fats Are Your Friend
Most of us grew up being told to avoid fat entirely. Butter, lard, and even healthy oils were treated as off-limits if you wanted to be fit and healthy. Keto flips that script, so it's worth reminding yourself, more than once, that fat isn't the enemy here.
Healthy fats genuinely work in your favor.
That said, this isn't a green light for ice cream, candy, or chips. Your fat should come from real, minimally processed sources. In the first few weeks especially, don't hold back on fat intake. The right amount varies from person to person, but giving yourself permission to eat enough fat is what keeps you full, steady, and able to stick with the process long-term.