Low Carb Diet vs Keto: What's The Difference and Which is Better?

If you thought a low-carbohydrate diet and a ketogenic diet were one and the same, you’re not alone. Most people get confused between the two diets and all of their similarities, but there are small differences between a low-carb diet and the keto diet that make them unique.

However, if you’re looking for better metabolic health, cardiovascular health, weight loss, better sleep, and overall just feeling healthier, chances are either one will do.

Which one you choose will depend on your end goal and how strict you want to be, or if you have a pre-existing medical condition that can be treated or improved through carb restriction.

So, we’re diving into low-carb diets and the ketogenic diet. We’ll be covering the differences between them, the health benefits of low-carb and keto diets, and which diet is better.

The Difference Between Low-Carb and Keto Diets

You’ll often hear people speak about a low-carb diet and keto diets as the same, and while there are a lot of similarities between them, they’re not exactly the same thing.

There are three macronutrients—carbohydrates (4 cal/g), fat (9 cal/g), and protein (4 cal/g). In most diets, carbohydrates make up the bulk of the diet, providing anywhere from 45-65% of total calories.

However, while there is no clear consensus on what low-carb diets entail, the general approach is to reduce carbohydrate intake well below that of the typical Western diet and consume moderate protein and moderate fat intake.

There are a couple of ways you can go about doing a low-carb diet ¹:

• Very low-carb diet—less than 10% carbohydrates or roughly 20-50 g/day
• Low-carb diet—less than 26% carbohydrates or less than 130 g/day

Alternatively, you have moderate-carbohydrate diets that consist of 26%-44% carbs and high-carbohydrate diets of over 45% carbs. Most people following low-carb are consuming a "low-carb diet)—less than 26% carbs.

It provides a bit more flexibility within your eating while still providing many health benefits. However, once you drop below that 10% threshold, you’re entering into keto diet territory where you're severely restricting carbs.

Here’s the typical breakdown of a low-carb diet:

• 10-25% carbohydrates
• 40-50% protein
• 30-40% fat

However, keep in mind that these ratios aren’t set in stone. They can change depending on what the individual needs.

Sometimes they may require less protein and more fat, but as long as they're keeping carbs low, they’re still eating low-carb.

The main difference between the ketogenic diet and low-carb is the macronutrient breakdown. The “very low-carb diet” we hit on above follows the principles of keto—less than 10% carbohydrates.

But the difference is that it’s not a free-for-all with the other two macronutrients because extra protein can be converted into glucose and kick you out of ketosis (we’ll get to what ketosis is shortly). Similarly, you also have to have enough fat to generate fuel and ketones.

Here’s the typical breakdown for a keto diet:

• 5-10% carbohydrates
• 15-30% protein
• 70-80% fat

As you can see, the ratios are pretty different. Ketogenic diets, also called low-carb high-fat diets, consist primarily of healthy fats that support the body’s ability to get into ketosis and burn fat for fuel.

They also restrict protein more than the traditional low-carb diet does because protein can undergo conversion to glucose through a process called gluconeogenesis and too much protein can prevent you from getting into ketosis.

Ultimately, you're consuming lots of fats, moderate protein, and low-carb to kick your body into fat-burning mode.

The premise behind the ketogenic diet is that when you severely restrict glucose—the brain’s preferred source of fuel—you force the body to find an alternate source of fuel.

When glucose availability is severely limited, the body’s demand to maintain serum glucose levels persists, which means it must generate fuel from elsewhere—that is, ketone ². The keto diet alters your metabolism to form ketone bodies (acetate, acetoacetate, β-hydroxybutyrate) from fat.

Normally, the use of ketones by the brain is minimal, but during the ketogenic diet, they partly replace glucose as brain fuel. They undergo conversion and then enter the Krebs cycle within brain mitochondria, leading to the production of ATP (energy) ².

Low Carb vs Keto: Which Diet Is Better For You?

Regardless of what diet you choose, reducing your carbohydrates will have significant positive impacts on your overall health.

It’s said that the increase in calories in the traditional Western diet over the past three decades is almost entirely attributed to an increase in consumption of high-carb foods ³.

And funny enough, there's also been a major increase in the prevalence of various chronic diseases like cardiovascular disease, heart disease, obesity, and metabolic syndrome.

But when we cut back on carbohydrates and increase intake of protein and healthy fats (and not necessarily reduce calorie intake), there are some major benefits the body can experience. Some of these benefits of reducing dietary carbs include:

• Reduced sugar cravings
• Reduced bodyweight
• Various improved markers of cardiovascular health
• Reduced risk of diabetes and heart disease
• Improved glucose and insulin function
• Lower blood pressure
• Enhanced cognitive function and health
• Increased energy
• Improved sleep

Current literature supports the efficacy of the keto diet and low carb diets for weight loss and improvements in health, but there’s also research showing that low-carb diets could be beneficial for treating health conditions that low-fat diets seem to exacerbate.

But figuring out the best low-carb diet approach can be challenging at the best of times when you’re bombarded with conflicting information from every angle.

Some information claims the keto diet is the best low-carb diet because you’re receiving the benefits of keto and low-carb simultaneously, while others lean towards low-carb because keto is inherently a restrictive diet and risky.

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With all of that said, there’s no one-size-fits-all model for diets and the best diet is going to be the one that works for you. Some people will do better on a ketogenic diet whereas others will do better on low-carb.

It’s going to depend on how your body reacts to shifts in macronutrients, but generally speaking, both are great for eliciting favorable health benefits.

Let’s go through some of the differences and benefits of both.

Keto vs. Low-Carb: Ketosis

If you’re going to follow a ketogenic diet, you have to be in a metabolic state called ketosis. Nutritional ketosis is a state whereby the body is burning fatty acids (ketones) for energy instead of carbohydrates (glucose or glycogen).

These fatty acids are metabolized into acetoacetate and later converted to beta-hydroxybutyrate and acetone ⁴. As ketones accumulate in the body, they create a state referred to as "nutritional ketosis." As long as the body is deprived of glucose, you’ll remain in a ketotic state.

Ketones can easily be used for energy by the heart, muscle, and kidneys but can also cross the blood-brain barrier to supply the brain with energy. But be prepared---that initial entry into ketosis can come with some nasty symptoms collectively referred to as the "keto flu".

However, being in ketosis is considered safe, as only small concentrations of ketones are produced without altering blood pH. Contrary to what some people think, it’s not the same as ketoacidosis, which is a life-threatening condition where ketones are produced in excess, causing the blood pH to drop into an acidotic state ⁴.

Keep in mind that to be following a ketogenic diet, you have to be in ketosis. Low-carb diets are still generally too high in carbs to enter ketosis, which means your body isn’t using fat for fuel and you're likely going to be feeling tired and cranky.

However, the only way to know if you’re truly in ketosis is through daily testing.

Testing for ketosis

This can be done with breath, urine, or blood strips.

Breath analyzers can be used multiple times, whereas blood and urine strips are single-use, making them more expensive in the long run. Blood and breath strips are generally more accurate, as urine strips only measure what’s excreted.

Keep in mind that it's possible to be eating low-carb without being in ketosis. However, that means that your body isn’t burning fat and using ketones for fuel.

Keto vs. low-carb: Weight loss

Weight loss is one of the most sought-after benefits of cutting carbs—but it’s not guaranteed. Technically, keto is a form of low-carb eating, but the main difference is that one you’re in ketosis and the other you’re not.

Carbohydrates are the primary fuel for the body and they’re the most readily stored. When you’re following a high-carb diet, any glucose that isn’t utilized is stored as adipose tissue. And, on average, most people consume them in excess, which means you gain rather than lose weight.

When you take away (or at least reduce) that readily available source of energy and storage, you’re reducing the likelihood of weight gain and supporting weight loss.

But there are a few reasons why low-carb diets work for weight loss ^5-10:

• Lower insulin levels—When carbs are restricted, insulin levels decrease and fat is mobilized to be burned for energy. It's impossible to dip into fat stores when insulin levels are high.
• Higher protein intake—Protein is inherently more satiating than carbohydrates but can also help to reduce appetite, boost metabolism, and increase muscle mass, all of which help to boost energy expenditure.
• Regulate appetite—A raging appetite is a major cause of weight gain and low-carb diets can regulate the hunger hormones leptin and ghrelin to reduce cravings and curb hunger.

People see such dramatic weight loss initially following a keto diet or low-carb diet because the body stores carbs (glucose) in the form of glycogen, which is bound to water in the muscles and liver.

When you cut back on carbs, glycogen levels in the body dwindle and the water follows along. That means you lose weight in the form of losing water. In the long run, you may not see that much weight loss, but one thing that’s generally guaranteed on a keto diet is that you will lose body fat.

Other Benefits Of Eating Low-Carb And Keto Diets

Glucose metabolism

When broken down, carbohydrates are converted into glucose (sugar), which is rapidly absorbed into the bloodstream and causes an increase in blood sugar concentrations.

Depending on the type of carb you’re eating (simple vs. complex), the effect could be immediate (simple) or more delayed (complex).

However, basic biochemistry agrees that a high carbohydrate diet will increase blood sugar (and subsequently insulin). Reducing carb intake will lower it ³.

Although blood glucose concentrations are sensitive to other macronutrients, carbohydrates elicit the greatest effect on both glucose and insulin, and reductions in insulin are seen following a low-carb diet and ketogenic diets.

A 2004 study looked at the effect of two isocaloric diets on blood glucose control in 8 men with type 2 diabetes ¹. Subjects were put on either a high-carb control diet or a low-carb diet.

At the end of the five weeks, the mean 24-hour serum glucose for the low-carb diet group dropped significantly compared to the control group. There was also a greater reduction in HbA1c and insulin levels in the low-carb group.

In short, reducing consumption of all forms of carbohydrates and increasing consumption of healthy fats reduces the effects of diet on blood sugar and insulin concentrations, which can elicit a lot of positive outcomes for several aspects of health.

Blood pressure

Obesity is a major factor involved in high blood pressure due to the increased size of the vascular bed that impairs blood flow from the heart and increases pressure in large arteries.

High circulating levels of insulin associated with obesity also impact sodium retention, the proliferation of vascular smooth muscle, increase sympathetic nervous system activity, and decrease the release of nitric oxide (a potent vasodilator) from the endothelium ³.

The reductions in blood pressure seen in people following low-carb diets are generally due to the weight loss accompanying the diet, but some research suggests other mechanisms independent of weight loss.

A 2009 study published in Cardiovascular Diabetology followed 200 subjects consuming either a low-carb diet or a low-fat diet, both of which were calorie-restricted (less than 400 cal/day) ¹².

At the end of the study, the low-carb group saw greater weight loss compared to the low-fat group, as well as a significant decrease in systolic blood pressure at 12 months; the low carb group saw a 5 mm Hg reduction compared to just a 1 mm Hg in the low-fat group.

Energy

The body derives most of its energy from glucose (carbohydrates), but when following a diet where glucose intake is restricted, energy can start to wane and leave you feeling fatigued and sluggish.

Because ketone bodies replace glucose as a source of energy for the brain on the keto diet, they may be effective for boosting energy levels. That’s because research shows that ketones may be a more efficient source of energy per unit of oxygen than glucose ¹³.

Here’s what we mean ⁴:

• 100g of acetoacetate yields 9,400g of ATP
• 100g of beta-hydroxybutyrate yields 10,500g of ATP
• 100g of glucose produces 8,700g of ATP

On top of that, the keto diet also upregulates mitochondrial genes, genes involved in energy metabolism, and appears to stimulate mitochondrial biogenesis ². Together, the availability of a more efficient source of fuel and greater numbers of mitochondria boost cellular energy production capacity and reserves.

Final Thoughts

In short, a keto diet may be more beneficial and healthier than low-carb if you’re dealing with any of the conditions above.

But keep in mind that consuming some carbs does play a role in health (primarily by contributing to hormone balance and replacing excess calories from fat).

Because of this, the keto diet may not work for some people, so adding in a small number of carbs and sticking to a low-carb diet may be more ideal for your health.

At the end of the day, you need to find what works for you and do it. No one diet is going to work for everyone, so it’s about experimenting and tweaking to find your body’s sweet spot.