Macros for a Low Carb Diet
Need to Know:
On a low carb diet, you would likely consume no more than 25% of your calories from carbs, leaving you to decide how to allocate the rest of the calories to protein and fat.
There are many different variations of a low carbohydrate diet and there isn’t necessarily a one-size-fits-all approach to reducing your carb intake.
The smartest carbs to consume on a low-carb diet include whole grains, cruciferous vegetables such as broccoli or asparagus, and fiber-rich fruit like berries.
Do you know how to calculate low-carb macros? Technically, a low-carb diet is one in which you consume less than 26% of your calories from carbs. So, if you consume 2000 calories per day, then you would consume (at most) 520 calories per day from carbs or roughly 130 grams of carbs per day. If you consume 1800 calories per day, you would consume 468 calories from carbs or 117 grams of carbohydrate per day.
Low-Carb Diet Macros vs. Balanced Macros
Let’s back up for a minute. Are you sure you want to go on a low-carb diet? Studies have yielded mixed results when it comes to this style of eating,(1) so let’s compare a low carb diet to a balanced diet.
On a balanced diet, you consume macros in amounts consistent with USDA health guidelines. Most of the benefits you gain from adopting this approach come from the fact that you are getting adequate amounts of protein, fat, and carbs. Doing so helps you maintain your energy throughout the day, build and repair tissue (like muscle!), and feel full and satiated all day long. When you decrease your intake of any nutrient below recommendations provided by nutrition experts, you shortchange yourself of balanced nutrition. The Dietary Guidelines for Americans (DGA) advise that you consume 45%-65% of your calories from carbs, 10-35% of calories from protein, and 20-35% of calories from fat. (2)
But low carb diets have been shown to be successful for weight loss, especially in the short term.(3) When you’re trying to lose weight, fast results can be helpful to boost your motivation. You will lose water weight quickly on a low carb plan, which can help you to feel lighter and slimmer right away. However, some studies have questioned the effectiveness of low-carb diets over the long term.(4)
The trick is to find a plan that works for you. If a low-carb diet is sustainable for you and you are able to reach your goals while following it, then you may not be inclined to change it.
Before choosing the best low-carb macro balance for you, consider all of the different choices. There are many different low-carb eating plans; not all require you to cut back your carbohydrate intake to below 26% of total calories. So, evaluate your options and find a plan that looks like it could be sustainable for the long term. A short-term fix can do more harm than good when it comes to weight loss.
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Low Carb Diet Macros: What Are Your Options?
There are different ways to go low-carb. If you currently consume a standard American diet (SAD), you may want to ease your way into a low-carb life. Your current diet is likely high in starchy carbohydrates (like pasta and white bread) which can be hard to give up. If you’ve decided to cut back on carbs, you may want to start with a higher-carb plan and gradually ease into a lower-carbohydrate program as you get more comfortable with non-starchy foods.
Atkins Diet
Macros: 55-75% fat, 20-30% protein, 5-15% carbohydrates (but can vary by stage)
The Atkins Diet, founded by Dr. Robert Atkins in the 1970s, is a variation of the ketogenic diet. There are different phases of the program and each has its own recommended macronutrient ratio. The diet, in general, is considered to be highly restrictive and is hard for many people to stick to.
When you go on the Atkins plan, you count net carbs rather than carbs. Net carbs is the number of total carbs (in grams) minus fiber grams and sugar alcohols.(5) During the initial phase of the Atkins 20 plan, called induction, you limit your daily net carb intake to just 20 grams. On the Atkins 40 plan (for people who have less than 40 pounds to lose) you consume 40 grams of net carbs per day.
The concept of net carbs is debated among nutrition experts. Certainly, counting net carbs instead of total carbs allows you to increase your total carbohydrate intake. But the science behind net carbs isn’t completely clear. Subtracting fiber grams from total carb grams assumes that fiber is not digested and, therefore, provides no calories at all. But this is not entirely true. Studies show that different types of fiber are digested differently. Soluble fiber does, in fact, contribute about two calories per gram. Insoluble fiber is not digested and contributes almost zero calories.(6)
However, most foods with fiber contain both soluble and insoluble types. Furthermore, nutrition labels do not distinguish between soluble and insoluble fiber. So there is no way to get an accurate idea of exactly how the fiber in a food contributes calories or energy to the body.
The Atkins diet may be best for someone who prefers a commercial diet where they can purchase pre-packaged foods and meals and enjoys access to branded resources, (like support groups, etc).
Low Carb, High Protein, Moderate Fat Diet
Macros: 25% carbs, 50% protein, 25% fat
This low carbohydrate diet will be challenging to sustain simply because the protein intake is relatively high. For comparison, a balanced diet would have you consume up to 30% of your calories from protein, so consuming 50% of your calories from protein may be challenging. But the diet would likely be easier to maintain than a more restrictive plan, like keto or Atkins.
This low carb plan may be smart for someone who is considering the ketogenic diet, but isn’t really to give up on carbs completely. This is also a smart plan for someone who wants to lose weight and build muscle. The amino acids (protein) you consume help to build and repair muscle tissue after a strength-training workout.
Moderate-Carb, Low-Fat Diet
Macros: 45% carbs, 35-40% protein, 15-20% fat
On this eating plan, you dial back both your carb intake and your fat intake. This allows you to consume more calories from protein, but less than you would on a true low carb diet.
This low carb plan may be smart for someone who is considering a lower carb, but wants to ease into it slowly. The low fat intake helps you to keep the calories a bit lower on this plan, so you are likely to see some weight loss, but not as much water loss in the initial stages. But water loss is not sustainable weight loss, so this plan may be more sustainable long term.
Expect to consume more meat, fish, or plant-based protein products on this diet. But since your fat intake is lower, you’ll have to choose sources wisely. Healthy foods like tuna, salmon, nuts, and seeds will be harder to include in meals and snacks simply because their fat content may be too high.
Moderate-Carb, Moderate Fat, High-Protein Diet (40/30/30 Diet)
Macros: 40% carbs, 30% protein, 30% fat
This is a fairly balanced diet as far as low-carb programs go. Your carb intake is lower than is recommended by the DGA but it is not nearly as low as the Atkins program or a ketogenic diet. Also, this program allows you to consume more fat than a low-fat program, so foods like avocados, olive oil, and nut butters can stay in your food plan.
The 40/30/30 diet is also known as the Zone Diet. The Zone Diet was founded by Dr. Barry Sears and has stood the test of time. Even though many find the diet to be restrictive, it remains one of the more popular weight loss programs in the commercial diet space.
Very-Low-Carb, High Fat Diet (Ketogenic Diet)
Macros: 5% carbs, 25% protein, 70% fat
Macros for this low-carb diet can vary. Also, the way people follow the program varies a bit. The ketogenic diet was first developed in the 1920s to help people with seizure disorders. The eating plan was shown to be helpful in reducing seizure episodes.(7) More recently, it has been adopted as a weight loss method, in part, due to the success of the Atkins program.
To follow a ketogenic, you need to keep the body in a state of ketosis. You consume only enough carbohydrate grams to force your body to burn fat as fuel. You’ll know that your body is in ketosis by testing for the presence of ketones in your urine.
Many people have been successful on the ketogenic diet, but the eating plan has come under scrutiny by health experts. It is very hard to consume fruits and vegetables on this program, so your vitamin and mineral intake may suffer. Studies have also suggested that the diet is generally not sustainable long-term.(8)
No Carb/Meat Only (Carnivore Diet)
Macros: 0-10% carbs, 65-80% fat, 20-35% protein
On a carnivore diet, you eat only meat. This extreme variation of a very low-carb diet is not sustainable for most people. Still, it is popular among some bodybuilders (especially during a bulking phase) and extreme athletes.
If you shift from a standard American diet to a carnivore diet, you can expect to feel extremely sluggish in the first few weeks as your body adjusts to complete carbohydrate depletion. Also, you’ll find that most typical foods are not allowed on this program. Instead, you will build meals around organ meats, animal-based fats, and eggs. You can consume full-fat dairy products, but since they contain carbs, you’ll need to keep your intake to a minimum.
As you might expect, your intake of important vitamins, like vitamin A and vitamin C are extremely limited on this diet. For this reason and several others, nutrition experts do not highly recommend the diet. (9)
Paleo Diet
Macros: 35% fat, 35% carbs, 30% protein
The Paleo diet also called the caveman diet, is similar to a carnivore diet but not quite as restrictive. On this diet, you limit your intake of starchy foods, but some carbohydrates are allowed, such as fruits, vegetables, mushrooms, nuts and seeds. You avoid dairy products, grains, legumes, and processed foods. For many people, this eating style is easier to maintain than a ketogenic or very low-carb diet because fewer foods are off-limits.
The Paleo diet became wildly popular among CrossFit athletes. However, many have criticized the theories behind the eating plan, stating that the diet doesn’t really represent what a caveman would have eaten.(10) Others call out the fact that a “cavemen diet” isn’t necessarily a smart diet for 21st-century people.
Choosing Carbs on a Macro Diet
Whether you are doing a low-carb macro diet or a balanced macro diet, you will benefit from choosing carbs that are full of vitamins, minerals, and fiber.
So, where do you find these carbohydrate foods? Check out the produce section, freezer section, and middle aisles of your grocery store and look for:
Whole or frozen fruit
Fresh or frozen veggies
Green leafy vegetables
Nutrient-rich starchy vegetables (like sweet potatoes)
Whole grain bread or pasta
Wild or brown rice or grains like tempeh, quinoa, or farro
There are countless options to choose from. In general, you’ll benefit from choosing carbs that are closest to their whole form. That is, they are less processed. Foods made with refined or enriched grains are going to be less nutritious.
We cover carbohydrates on the macro diet in Macro Diet for Dummies. I provide grocery shopping lists and go into detail about how many carbs you should consume each day. Pick up a copy and follow me on Instagram and Facebook to learn more about your optimal carb intake on the macro diet.
Sources:
Landry, M.J., Crimarco, A. & Gardner, C.D. Benefits of Low Carbohydrate Diets: a Settled Question or Still Controversial?. Curr Obes Rep 10, 409–422 (2021). doi:10.1007/s13679-021-00451-z
Chawla S, Tessarolo Silva F, Amaral Medeiros S, Mekary R, Radenkovic D. The effect of low-fat and low-carbohydrate diets on weight loss and lipid levels: a systematic review and meta-analysis. Nutrients. 2020;12(12):3774. doi:10.3390/nu12123774
Barber TM, Hanson P, Kabisch S, Pfeiffer AFH, Weickert MO. The low-carbohydrate diet: short-term metabolic efficacy versus longer-term limitations. Nutrients. 2021;13(4):1187. doi:10.3390/nu13041187
Atkins. What Are Net Carbs?
Hervik AK, Svihus B. The Role of Fiber in Energy Balance. J Nutr Metab. 2019 Jan 21;2019:4983657. doi:10.1155/2019/4983657
D'Andrea Meira I, Romão TT, Pires do Prado HJ, Krüger LT, Pires MEP, da Conceição PO. Ketogenic Diet and Epilepsy: What We Know So Far. Front Neurosci. 2019 Jan 29;13:5. doi:10.3389/fnins.2019.00005
Batch JT, Lamsal SP, Adkins M, Sultan S, Ramirez MN. Advantages and Disadvantages of the Ketogenic Diet: A Review Article. Cureus. 2020 Aug 10;12(8):e9639. doi: 10.7759/cureus.9639
Goedeke S, Murphy T, Rush A, Zinn C. Assessing the Nutrient Composition of a Carnivore Diet: A Case Study Model. Nutrients. 2024 Dec 31;17(1):140. doi:10.3390/nu17010140
Singh A, Singh D. The Paleolithic Diet. Cureus. 2023 Jan 25;15(1):e34214. doi:10.7759/cureus.34214