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Low Carb Diet vs. Keto: Which to Choose Based on Your Health Goals

10 min read
keto vs low carb diets
Sarah Jackson Damuth post Reviewer Sarah Jackson Damuth post Reviewer
MS, Registered Dietitian Nutritionist, Certified LEAP Therapist

Have you wondered about the differences between the low-carbohydrate diet and the ketogenic or “keto” diet? Is one better than the other for weight loss? Read on to learn more about these low-carbohydrate options.

Table of Contents

The diets overview

Both the low carb and the keto diet, are popular in Western society due to the purported claim that they help to burn adipose tissue and increase insulin sensitivity thereby decreasing the risk of insulin resistance.

Keto diet

The ketogenic diet, also known as the keto diet, is a diet regimen extremely low in carbohydrates, high in fat, and has a moderate amount of protein. The basis of the keto diet is to reach the state of ketosis, where the body uses ketone bodies as its primary fuel source instead of glucose.

The body typically utilizes glucose from carbohydrates for energy. The premise of the keto diet is to consume small amounts of carbs so that the body is forced to use stored ketones in fat tissue. The accumulation of ketones in the blood and low levels of glucose is a sign that an individual is in ketosis.

The keto diet has many potential side effects, and its effectiveness in long-term weight loss is controversial due to the lack of longitudinal research (source: Harvard School of Public Health).

Low-carb diet

Similar to the keto diet, the low-carb diet recommends consuming a low amount of carbohydrates overall but it is less restrictive and focuses on high protein rather than high fat intake. 

The goal of the low-carb diet is not specifically to reach a state of ketosis, nor does it necessarily contain very high amounts of fat. The low-carb diet emphasizes the consumption of protein and fat, which are more satiating than carbs. This is why researchers believe that low-carb dieters tend to eat less overall and thus shed undesired weight. Several studies have demonstrated that following a low-carb diet can lead to weight loss for 12-24 months and improve insulin sensitivity.

It is important to note that we can consider the keto diet a low-carb diet because carbs are restricted, but the low-carb diet is not necessarily ketogenic. When the amount of carbohydrates gets restricted very severely, then ketosis can occur.

Low-carb dietKeto diet
Limits carbs
Puts your body in ketosis
High-fat diet (up to 70% of calories)Not necessarily
High-protein diet
low-carb vs. keto

As you see, both diets have their own mechanisms, risks, and benefits. So let’s dive into it!

What happens when we eat carbs?

As we compare how both diets limit carb intake, we will focus on what happens in our bodies when we eat carbs and why people choose eating regimes that moderate carbohydrates. 

Carbohydrates are typically found in grains, starchy vegetables, legumes, dairy, and fruit. Carbohydrates can be simple, complex, and refined. We consume simple carbohydrates eating dairy and fruit, complex carbs in beans and whole grains, and refined carbs in candy and white flour products, to name a few.

Many fast foods and processed foods are high in sugars and, therefore, high in carbohydrates as well.

All types of carbohydrates are broken down in the body into molecules of glucose, which can be used for energy. The difference, however, is in the amount of glucose that ends up in the bloodstream.

what happens when we eat carbohydrates
Glucose levels in the bloodstream after eating various carbs

When carbs are consumed in the diet, the sugar enters the bloodstream, causing an increase in blood sugar. When the pancreas receives the signal that the blood sugar is high, it releases an important hormone known as insulin. Insulin lets the cells open up so that the sugar in the blood can enter and eventually be used to create energy to power the whole body.

Furthermore, when the glucose enters the cells and is no longer in the blood, the pancreas is signaled to stop producing insulin

The core issue with a high-carb diet

The modern Western diet is typically very high in carbs and normalizes large restaurant portions, which can lead to health problems, such as cardiovascular disease and type 2 diabetes. In addition, according to Johns Hopkins Medicine, excessive sugar intake can significantly contribute to weight gain and obesity.

Due to the abundance of research linking obesity to excessive refined sugar intake, low-carb diets have become very mainstream.

Keto, low-carb & high-carb diets

The following table shows the differences between the USDA guidelines for a regular balanced diet and the low carb and keto diets in net carbs intake (source: Mayo Clinic).

Net carbs are digestible carbs that can be fully processed into glucose. Unlike total carbs, net carbs don’t include fiber and sugar alcohols.

low carb diet vs keto carbs
Comparison of carb intake in keto vs. low-carb vs. high-carb diets

Compared to a USDA diet, or a “regular” diet, the low-carb diet has significantly fewer carbohydrates. While it can vary slightly, the low-carb diet typically has 10% to 20% calories from carbohydrates. 

The USDA diet is appropriate for many individuals. However, it can be harmful if most carbohydrates are from processed foods, such as fast food and packaged items with added sugars. 

Additionally, excess body fat and carbohydrate intake can potentially contribute to insulin resistance, or decreased insulin sensitivity can occur (source: Cleveland Clinic). 

Insulin resistance means the cells in the body that should respond to insulin by letting glucose into the cell don’t function properly. In other words, the cells do not respond to insulin, thereby remaining in the bloodstream, leading to elevated blood sugar levels. The condition is associated with prediabetes, Type 2 diabetes, and obesity.

Indicators to know before choosing your low-carb diet

Before choosing if you would like to begin a low-carb diet, it is essential to consider the risks. 

Carbohydrates are an energy source, so suddenly reducing carb intake can contribute to headaches, muscle cramping, and even diarrhea

When the carb restriction becomes even more extreme (as for the keto diet), you may experience mood issues, tiredness, hunger, brain fog, headache, and more (source: Harvard School of Public Health). 

Consuming the USDA guidelines for carbohydrates alleviates these symptoms. 

Next, let’s discuss some factors that may influence your choice of a low-carb diet regimen.

#1 Insulin resistance (IR)

The prevalence of insulin resistance in obesity is quite common; therefore, that’s where we should begin. Researchers and scientists have created the homeostasis model assessment-insulin resistance indicator, or HOMA-IR indicator, to measure insulin resistance. This indicator essentially tells you how much insulin is needed to control blood sugars (source: Self Decode). Therefore, the lower the HOMA-IR, the less insulin resistant you are.

  • The normal HOMA-IR range is less than one (plus or minus a few tenths);
  • The value above 1.9 indicates early insulin resistance;
  • Above 2.9 is severe insulin resistance;
  • Elevated HOMA-IR levels, even up to 10, indicate insulin resistance and may be correlated to diabetes.

While the HOMA-IR indicator itself may be insufficient for choosing a diet, limiting carbohydrate intake, such as in the low-carb diet, can help improve HOMA-IR levels or even lead to type 2 diabetes remission.   

People with a normal HOMA-IR value should consider limiting carbs in their diet to prevent insulin resistance which is still likely to develop if you stick to a high-carb diet.

#2 High fasting glucose

When an individual has insulin resistance, they typically have high blood glucose because the sugar cannot leave the blood and enter the cells. Insulin resistance is associated with those who consume high-carbohydrate, highly processed dietary patterns that are high in saturated fat.

Additionally, the pancreas accommodates insulin resistance by generating more significant amounts of insulin. However, if the cells become too resistant to insulin, eventually, this can contribute to the development of type 2 diabetes mellitus. 

Insulin sensitivity can be increased by consuming fewer carbohydrates since they stimulate high insulin production. Therefore, consuming a low-carb diet rich in whole grains can help improve insulin resistance and increase sensitivity.

#3 High insulin

We’ve clarified that after consuming a high refined-carbohydrate diet for long periods, an individual might experience insulin resistance. When you have high blood sugar, your body produces insulin to lower glucose but the cell becomes resistant to allowing it in. As a result, you have high blood glucose, which can cause several health complications over time. 

But what if you’ve already limited carbs, say, for a few months, but your HOMA-IR is still high? Even if there are very few carbs in your diet, your body can still produce a lot of insulin as it used to do when you had a high-carb diet, and your cells will still be insulin resistant, not responding to lifestyle changes. 

#4 Weight loss history

If you follow a low-carb diet for a few months, but your blood tests still show insulin resistance, it’s time to consider your weight loss history. Here, we have two major cases:

  • you couldn’t lose any weight following a low-carb diet
  • you lost some weight at the beginning but reached a plateau  

Both of them signal that you may benefit from switching to keto and significantly limiting (but not removing completely) carbs in your diet for some time which should be determined by your healthcare provider. 

Final comparison: which one to choose to lose weight?

There is strong evidence that a keto diet is an effective tool for weight loss. However, the ratio of carbohydrates, fat, and protein must be very accurate. Therefore, the keto diet is very strict and disciplined. It is not recommended to follow highly restrictive diets, such as the keto diet, if you have a history of disordered eating or an eating disorder. 

Additionally, the keto diet, initially designed for treating epilepsy, has not often been studied in the long term for those trying to lose weight. More research is needed to confirm long-term effectiveness. However, the strict nature of the diet often leads to non-compliance. 

The low-carb diet, which is more of a sustainable approach to carb restriction, is easier to sustain for long-term weight loss as it is less restrictive and more balanced than the keto diet. 

Consuming a low-carb diet to control blood sugars and reduce insulin levels. Additionally, staying physically active, increasing non-exercise activity, and adding low-intensity training to your schedule can be helpful for controlling blood sugar levels. You can also use a calorie and activity tracking app to record your weight loss flow.

Final takeaways of the keto and low-carb diets

Keto DietLow-Carb Diet
✅✅✅ Helps get past a weight-loss plateau ✅✅✅ Helps lose weight following a less strict, more sustainable diet 
✅✅ Lose weight and burn fat faster; however,
much more restrictive and severe
✅✅ Can be a part of a balanced diet 
✅ Under medical supervision, may help
with hormonal imbalance, chronic inflammation, autoimmune conditions, etc.
✅✅ Helps normalize blood sugar and insulin production
✅ Blood sugar improvements;
improved glucose metabolism and weight loss for patients with type 2 diabetes
❌ Risk of side effects, including headache and diarrhea
❌ ❌ Higher risk of nutritional deficiencies and
❌ More significant side effects, including mood changes and brain fog

Following a low-carb diet can be an effective way to lose weight. However, the more severe the carbohydrate restriction (the keto diet is the most strict), the more short-term the weight loss typically is. 

In other words, the keto diet often is difficult to maintain in the long term since it is so restrictive. Therefore, the moderately low-carb diet, with net carb consumption between 25 to 150 grams, is the best choice for sustainable weight loss. 

You may also choose to continue consuming a “regular” carbohydrate diet of 275 grams per day or 45% to 65% of calories from carbs in an average 2,000-calorie diet. If you do, ensure that at least half of the grains are from whole grains and that less than 10% of calories are from added sugar. 

However, if you decide to begin the keto diet since it is so strict, it is essential to consult your physician and registered dietitian before starting the diet.

Disclaimer This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!

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