There is no denying that keto diets and low carb diets are becoming increasingly popular with those looking to shed a few stubborn pounds. Both diets have been around for many years, but what’s the real difference between the low carb diet and the keto diet?
Which of the two works best for burning fat? Both the low carb diet and the keto diet are low in carbohydrates and high in fat. However, they have a different mechanism.
To remove all the mystery and myth, we took a detailed look at the keto diet and low carb diet, as well as some of their benefits and potential risks.
What you'll read:
What is a keto diet?
A ketogenic diet (keto diet) is a diet that is high in fat, moderate in protein and low in carbohydrates. A keto diet forces the body to produce something called ketones, which is a fuel source that is used when glucose stores are low.7 Ketones come from adipose tissue (body fat) and go through a “conversion process” in the liver to become a ketone body.
The most common breakdown for a keto diet is 70% fat, 25% protein, and 5% net carbs. Net carbs are often overlooked, but it’s simply total carbs minus dietary fiber, which gives you net carbs.
If someone were to eat a 2000 calorie diet, then the macronutrient breakdown would be 156g of fat (70%), 125g of protein (25%), and 25g of net carbs (5%).
So why do we even need ketones? Well, it turns out they’re a pretty important backup system if high-energy foods – like carbs – become scarce.
The preferred fuel source for the brain and nervous system is glucose, which is readily available in the body. With the keto diet having such a low amount of carbohydrates, stored carbohydrates are often depleted within days.
This forces the body to use fat as its primary energy source. Fats, however, are unable to cross the blood-brain barrier, leaving the brain short of fuel. If the brain was unable to obtain any fuel, then the entire nervous system would shut down.
Ketones, however, are able to easily cross the blood-brain barrier and provide the brain and nervous system with a second preferred fuel source.
What is the low carb diet?
Unlike the keto diet, there is no clear definition for the low carb diet, i.e. a low carb diet.8
The consensus seems to be that protein is high – anywhere from 1.4 g / kg to 2.2 g / kg – while fat is moderate and carbohydrates are lower than the average of the Western diet but higher than the keto diet.
This could mean that on a low-carb diet, carbohydrates could range from 50 to 150g per day. Much of what determines whether a diet is low in carbohydrates comes down to the person’s body weight
For example, if a 50kg woman had 130g of carbohydrates per day, then this could be a moderate to high carbohydrate diet. However, take the same 130g of carbs and apply it to a 100kg male and it becomes a low carb diet.
The low carb diet predominantly uses fats as fuel, but to some extent proteins and carbohydrates are also available.
A low-carb diet is designed to help cope with hunger, keep insulin low, and prevent carbohydrates from being stored as fat – this can often lead to weight loss.
What’s really happening is that since there is less food to choose from (mainly protein and fat), it can be easy to stick to a calorie deficit. It is the calorie deficit that is responsible for weight loss and not the management and storage of carbohydrates.
Keto Diet vs. Low Carb Diet
Watch Video: Keto diet VS low carb diet
The keto diet is an aggressive version of a low-carb diet and requires a much stricter breakdown of macronutrients. It is an inflexible diet, which requires a lot of commitment to follow it as it has very restrictive rules, i.e. too much protein can ruin a ketogenic diet.
A low carb diet might be a bit more flexible as a wider range of carbohydrates are allowed. This could allow someone to eat a wider variety of foods, including healthy fruits and vegetables. A low-carb diet tends to be higher in protein, so depending on what foods you like, it may be easier to stick to it.
In terms of sports performance, there is little evidence to support either diet being better than the other. Longer-lasting sports will rely more on fat as an energy source, but as the intensity increases, carbohydrates are needed.7
What has become more popular recently is an occasional “low intent training” or “low recovery” approach. This means that an athlete intentionally has certain training sessions with low carbohydrates in the system or does not recover with carbohydrates. This forces the body to improve its effectiveness in using fat as fuel.
Since sports performance is often lower on the low carb diet, as muscles have less energy to use, it is important not to forget to train at maximum intensity at other times with carbohydrate consumption. The better the training you have, the faster you will reach your goals.
The Keto diet does not have the same benefits, as it takes time to adapt and produce ketones, which is not practical for a competing athlete.
What are the benefits of the Keto diet?
Most of the benefits of keto diets relate to adherence and food preference. There is nothing worse than feeling hungry from a diet. However, people who follow this diet claim that the keto diet suppresses appetite and the sense of hunger appears to decrease. This is down to ketone bodies and their effects on appetite, but not everyone feels the same sense of satiety.
The keto diet is a protein-sparing diet, which means that ketone bodies prevent proteins from breaking down to be used as fuel. While not an optimal diet for muscle gain, it could be used to maintain lean muscle mass. 10
To date, there is no substantial evidence on the impact of the keto diet on sports performance. 9
However, in clinical research, there is a growing body of research supporting the ketone diet and its usefulness on neurological disorders
But for now, it’s safe to say that if a keto diet allows you to eat without feeling deprived and can easily put you in a calorie deficit, it can be a good option for weight loss.
What are the benefits of low-carb diets?
A low-carb diet can easily put someone into a calorie deficit without having to track calories. Studies show that by limiting a food group, we tend to eat less on average 12. A less frequent choice often leads to eating less, which equates to weight loss. So, this could be a good diet if you are looking to lose weight.
With increased weight loss, health markers often show improvement. The risk of diabetes, high blood pressure and other health problems have been linked to being overweight. By losing weight these risks tend to decrease substantially. A low carb diet could simply make it very easy for people to achieve weight loss. 8
It is also a high protein diet. High-protein food is good for satiety levels, keeping you full for longer. It also helps prevent unwanted muscle breakdown, which can negatively impact health and performance.
What are the risks of the Keto diet?
A keto diet does not place a limit on saturated fat. Saturated fat has been associated with an increased risk of heart disease. There is a potential risk of health problems if you are already overweight and follow a keto diet that causes you to have excess calories, as this would mean further weight gain.
Some of these risks could be minimized in a calorie deficit, but it would be a good idea to get most of the fat from an unsaturated source.5 Type 1 diabetics should not follow a keto diet as it can lead to ketoacidosis which is a medical emergency.3 This type of diet is also not recommended for pregnant and breastfeeding women. 3
This recommendation is better to say that the recommendation is inferred due to a lack of evidence.
There is an increased risk of lack of fiber and the vitamins and minerals that come from vegetables – this could have a negative impact on health.
If someone is on a keto diet, then there is often an adjustment period. This could mean low energy, low mood, and brain fog. While it’s not a risk and tends to go away in a few weeks, it’s good to be aware of this.
What are the risks of the low-carb diet?
As we discussed earlier, low-carb diets don’t have a clear definition and can range from 50 to 150g per day. On the lower end, the risks could be similar to a keto diet, as a limited amount of carbohydrates also means limited fruits and vegetables. 8
Scientific opinion is uncertain whether the low-carb diet is healthy or not. There are some studies that show health benefits, but also others that give opposite results. The results could be very different between a caloric surplus and a deficit.
Low carb diets and keto diets are generally focused on weight loss, and for some, they can work very well. Others don’t feel as good and end up giving up on a more traditional carbohydrate diet.
One of their biggest selling points is that they decrease your appetite and give that feeling of satiety. However, low-carb and keto diets tend not to be ideal for sports performance or high-intensity exercise.