The ketogenic, or keto, diet is a very low carb, high fat eating pattern that has skyrocketed in popularity in recent years.
It has been shown to offer several impressive health benefits — including weight loss. Thus, many people turn to this way of eating to reach their weight loss goals.
While research indicates that the diet can help shed body fat, long-term studies supporting its effectiveness are lacking.
This article reviews the keto diet’s potential to aid weight loss.
When following the traditional keto diet, your carb intake is limited to less than 5–10% of your total daily calorie intake (1).
This allows your body to enter ketosis, a state during which the body switches to using fat instead of carbs as its primary fuel source, and ketones are produced in the liver (1).
The reduced carb intake is usually made up for by increasing fat intake to around 70–90% of calories, or 155–200 grams for a 2,000-calorie diet (1, 2).
Protein intake is moderate, usually around 20% of calories, or 100 grams for a 2,000-calorie diet (1, 2).
There are several proposed weight loss mechanisms associated with the ketogenic diet, though long-term studies are lacking.
May reduce hunger
One of the main weight loss mechanisms related to the keto diet is likely its ability to reduce hunger (4, 5).
Following the ketogenic diet has been linked to decreased levels of ghrelin, one of your body’s main hunger hormones (6).
Reducing ghrelin levels and hunger can cause you to eat fewer calories throughout the day, which may result in weight loss (6).
In fact, one study in 20 people with obesity following the keto diet associated this way of eating with reduced food and alcohol cravings (7).
Thus, the keto diet may be an effective strategy to regulate your hunger levels, though its long-term safety must be taken into consideration.
Can promote loss of water weight
Another potential weight loss mechanism of the keto diet is the loss of water weight that accompanies the significant reduction in carb intake.
This is because carbs, in their stored form in your body, hold water (8, 9).
Thus, when you reduce your carb intake, such as during the initiation phase of the keto diet, stored carbs are released along with additional fluid, resulting in weight loss of varying amounts.
To determine whether the keto diet can aid weight loss, it’s important to review how weight loss is traditionally achieved.
To lose weight, you must eat fewer calories than you burn, which is also referred to as a calorie deficit.
One study in 17 men with obesity or excess weight found that the keto diet was associated with a small increase in the number of calories burned. Although, this did not lead to increased body fat losses, compared with a traditional baseline diet (3).
These results suggest that the ketogenic diet is not necessarily superior to a traditional diet for weight loss when calorie intake is matched.
The keto diet’s weight loss effects are therefore much more likely to be a result of reduced calorie intake due to changes in satiety signals associated with high fat, very low carb diets.
The keto diet has been associated with weight loss, though the exact mechanisms remain unclear. Studies suggest that weight loss related to the keto diet is likely due to a calorie deficit, reduction in hunger levels, and water weight loss.
Since the keto diet’s surge in popularity, numerous supplements catered to keto dieters have appeared on the market, and some of them may aid weight loss.
Here are the top keto supplements along with their proposed functions:
- MCT oil. This oil, which contains medium-chain triglycerides, can help keto dieters add more fat to their diets and stay in ketosis. It’s digested more rapidly than traditional fats but can have digestive side effects.
- Exogenous ketones. These are ketones from an outside source, as opposed to naturally produced endogenous ketones. They can increase blood ketone levels and help you achieve ketosis more rapidly (10).
- Keto protein powders. These protein powders are formulated to have a low carb content.
- Keto electrolytes. Electrolyte depletion is common when first starting a keto diet due to water weight loss. Electrolyte supplements can help prevent deficiency of common electrolytes, such as sodium, potassium, and magnesium (11).
- Digestive enzymes. Due to the high fat content of the keto diet, some people may experience digestive issues. Digestive enzyme supplements, specifically lipase, can help break down fats.
When it comes to the weight loss effects of ketogenic supplements, studies are limited.
One study in mice looked at the viability of exogenous ketones as weight loss supplements. It found that several exogenous ketones, as well as MCT oil, may aid weight loss by reducing hunger and causing you to naturally eat fewer calories (12).
Still, human research supporting these claims is lacking.
While keto supplements are not necessary, they can help keto dieters transition into this rather restrictive way of eating and increase the tolerability of the diet.
That said, these supplements should not be used solely for weight loss, as the data is insufficient and their long-term side effects are unknown.
MCT oil and exogenous ketones can help you get into ketosis quicker and avoid many of the side effects associated with the transition. While they may also reduce appetite, it’s not recommended to use them as weight loss supplements.
When following a keto diet for weight loss purposes, some other factors also need to be kept in mind to ensure progress.
Your exact carb intake
When starting a ketogenic diet, it may help to keep track of exactly how many carbs you are consuming daily.
This helps ensure that you enter ketosis relatively quickly and avoid some of the symptoms associated with the “keto flu,” which is a group of symptoms, including headaches and brain fog, related to starting a keto diet.
If you eat too many carbs, you will not stay in ketosis, and the potential benefits of the diet, including weight loss, will be diminished.
For most people, eating less than 50 grams of carbs per day should be sufficient to stimulate ketosis (2).
Whether you’re getting enough sleep
Sleep is an often overlooked aspect of any diet. Studies show that a lack of sleep and chronic stress can negatively impact weight loss outcomes. This holds true when following the keto diet (13).
Studies also suggest that a lack of sleep can negatively impact hunger hormones, such as ghrelin and leptin. This can cause increased appetite, counteracting the hunger-reducing effects of the keto diet (14).
Ensuring that you take time to unwind and get at least 7 hours of sleep per night can help support the benefits of a ketogenic diet (15).
Whether you’re physically active
While the keto diet alone may provide weight loss, combining it with a proper exercise regimen can enhance this effect (16, 17).
When adapted to the diet, your body can use fat as its primary fuel source for exercise. Studies suggest that this is most beneficial in endurance-based sports (18, 19, 20).
It’s important to note that you should be well adjusted to the keto diet before performing any moderately intense exercise to avoid negative side effects.
When it comes to weight loss on the keto diet, several other factors need to be considered, such as your specific carb intake and sleep and exercise routine.
One of the major downsides of the keto diet — especially for weight loss — is long-term sustainability.
Considering that the diet is quite restrictive, some people may find it difficult to adhere to.
It particularly creates challenges when dining out or gathering with family and friends for the holidays, as a new way of eating must be adopted, potentially affecting social interactions.
Furthermore, studies on the health effects of following the keto diet for long periods are lacking (21).
These factors must be considered before starting it.
Due to its restrictive nature, the keto diet may be difficult to stick to in the long term. Eating out and other social situations may require particular diligence and preparation.
The keto diet is a very low carb, high fat diet that has been shown to offer various health benefits, including weight loss.
While the exact weight loss mechanisms associated with this way of eating are still under investigation, it appears that weight loss is caused by a calorie deficit, reduction in hunger levels, and water weight loss.
Keto supplements may reduce hunger and help you get into ketosis more rapidly, though they should not be used to promote weight loss.
While the weight loss benefits of the keto diet may seem promising, it’s important to consider its potential side effects, downsides, and the lack of long-term research on it.