What is a Good Ratio for a Low Carb Diet

Max Carmody, MSc

A good ratio of macronutrients for a standard low carb diet is 5-15% carbs, 40-50% protein, and 30-35% fat. Ratios differ and favor fat more than protein on different variations of the low carb diet, such as the keto diet, however.

What is a “ratio”?

To be clear, when I talk about ratios, I am talking about ratios of macronutrients. Macronutrients are “the nutrients your body needs in large amounts, which include fat, carbohydrates, and protein.”

Carbohydrates are the primary fuel for the body. They provide energy for the central nervous system and muscles during exercise or movement. Carbohydrates are sugars, starches, and fibers found in vegetables, fruits, grains, and milk products.

Protein is essential to multiple processes within the body. It provides structure to tissue including “Cell membranes, organs, muscle, hair, skin, nails, bones, tendons, ligaments, and blood plasma”. Individual needs for protein will vary depending on activity level, medical conditions, age, and health goals. Protein is essential to building muscle mass, and is usually found in animal products, although it can also be found in things like nuts and legumes.

Fat is used by the body as an energy reserve, for insulating and protecting the organs, and for transporting and absorbing fat soluble vitamins. Fat gets a bad reputation, but a small amount of fat is actually necessary for a healthy, balanced diet. Fat is a source of the fatty acids which the body cannot make itself. All types of fat are very high in energy, more than both protein and carbohydrates.
A macro ratio “expresses the total share of energy that comes from each macronutrient (protein, carbohydrate, and fat) in a food, meal, or diet. E.g the American diet is 15% protein, 50% carbs, and 35% fat. Macro ratios are a good way of getting a simple and quick understanding of where the energy is coming from in a diet, meal, or food. Macro based diet design tends to be done in grams per unit bodyweight.

Ratios for a Low Carb Diet

There is not one exact perfect ratio for a low carb diet. According to diet doctor to lose weight you will want a ratio of 5-15% carbs, 25-35% protein, and 45-65% fat. Notice how much lower the ratio of carbs is compared to the average daily % of carbs that Americans are eating, 5-15% compared to 50%. This ratio is also quite high in fat.

According to some, 5-15% is a good ratio of carbs, however, you will want your protein to outweigh your fat. One suggestion for a low carb ratio is 5-15% carbs, 40-50% protein, and 30-35% fat.

Both suggestions include very low carbs (because we are talking about low carb diets) but which is a better approach, high fat, or high protein? This is not necessarily the absolute correct answer, and it is somewhat a matter of opinion, but personally I would prefer a diet high in protein and not as high in fat.

Few studies have directly compared high protein low carb with high fat low carb diets, so there are few conclusive answers. However, according to livestrong, in some studies the high protein consumption actually appears to be more important than the low-carb part. One of the things that I have against high fat diets is that it can be easy to fall into the trap of consuming too much saturated fat, such as that in butter, which is generally considered to be unhealthy. However, it’s not great to consume too much protein either.

I suspect that also, there is not necessarily one “correct” diet for everyone, and that different diets work for different people. For example, even if you lost the exact same amount of weight on a high fat diet as on a high protein diet, you might just find that one was more likely to stick to than the other, for you personally. And this could make a big difference in long term gains. If you want to read about how many carbs you should eat per meal on a low carb diet, here is another article I wrote on the topic that you may be interested in.

Ratios for a Keto Diet

A keto or “ketogenic” diet is a specific type of low carb diet. According to healthline.com the keto diet “is a very low carb, high fat diet that shares many similarities with the Atkins and low carb diets. It involves drastically reducing carbohydrate intake and replacing it with fat. This reduction in carbs puts your body into a metabolic state called ketosis. When this happens, your body becomes incredibly efficient at burning fat for energy.” Eating high amounts of protein can prevent ketosis, so the protein amount is kept more moderate on the keto diet than other low carb diets.

There is not one “standard” ratio of macronutrients for the keto diet. Different people have different opinions on the topic. It does seem though, that most keto diet experts believe that more fat should be consumed than protein. Most keto diet resources however, “suggest an average of 70-80% fat from total daily calories, 5-10% carbohydrate, and 10-20% protein. For a 2000 calorie diet, this translates to about 165 grams fat, 40 grams carbohydrate, and 75 grams of protein.

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