Low carb and keto diets have become extremely popular over the past few years.
If these diets are designed well and emphasize the right foods, then they can be very healthy.
Like all diets, they have their advantages and disadvantages, but many people wonder about the potential benefits they offer.
This article examines the studies and science behind both diets and provides an evidence-based guide to the health benefits.
1. Low Carb Diets Are Clinically Proven For Weight Loss
Many people find that low carb and keto diets work exceptionally well for losing weight.
Firstly, these diets have several significant advantages in relation to what I would call "enabling" weight loss;
Systematic Reviews Favor Low Carb As a Weight Loss Method
There are many ways we can lose weight, and weight loss doesn't rely on following one particular diet.
Yes, it is true; we can lose weight on a low-fat, medium-fat, or any other diet.
This advantage remains whether the study lasts for 3, 6, or 12 months.
Key Point: The science is clear: well-designed low carb diets consistently perform well in weight loss interventions. Additionally, they outperform low-fat diets in these studies.
2. Can Help Manage and/or Reverse Type 2 Diabetes
Low carb and ketogenic diets are a popular nutrition intervention for those with type 2 diabetes.
Notably, one of the biggest merits of low carb diets is that they can beneficially influence -- and help control -- blood glucose and insulin levels (5).
Recently, Virta Health, a company who claim to offer a "clinically-proven method" to treat type 2 diabetes, released the results of a 12-month controlled study on 349 adults (6).
Their method is based on a very low intake of dietary carbohydrate and continuous health coaching. The results showed that all patients in the program experienced a reduction in fasting blood-glucose levels, lost weight, and reduced their diabetes-related medications.
Additionally, systematic reviews of randomized trials support these findings.
Key Point: Very low-carbohydrate diets are effective for the management of type 2 diabetes.
3. Low Carb Diets Reliably Increase HDL ("Good Cholesterol") Levels
High-density lipoprotein (HDL), commonly known as "good cholesterol", is associated with reduced risk of cardiovascular problems (10).
Dietary fat intake tends to increase circulating levels of HDL, and since low-carb diets are typically high in fat, they usually result in a significant increase in HDL levels.
Numerous studies have examined the effect of low-carbohydrate diets on HDL levels.
Based on current science, this rise in HDL should be a protective factor against cardiovascular risk.
Key Point: Low carb diets are good for increasing HDL cholesterol, which may result in lower cardiovascular risk.
4. Dramatic Reductions in Triglyceride Levels
Triglycerides are a kind of lipid (fat) found in our blood.
However, just because they are a type of fat doesn't mean they are related to dietary fat intake (a pervasive myth).
Triglycerides are a storage form of fat, and they have a relationship with (overeating) carbohydrate.
First of all, if we consume an excessive amount of (particularly refined) carbohydrate, our liver will convert the excess glucose into triglycerides.
This process is one of the reasons why diets full of sugar and refined carbohydrates are so unhealthy, particularly when combined with a sedentary lifestyle.
On the positive side, diets that reduce carbohydrate to low-moderate levels encourage lower triglyceride levels. This reduction in triglycerides is a consistent finding in high-quality studies on low carb diets (14, 15, 16).
The importance of this point is that cardiovascular scientists view higher triglyceride levels as being a significant risk for cardiovascular disease.
In particular, some cardiovascular researchers believe that the triglyceride to HDL ratio (which should ideally be low) is possibly the most reliable marker of cardiovascular risk (17).
Key Point: The effect on triglyceride levels is one of the biggest advantages of low-carb/keto diets. Eat less carbs and triglyceride levels tend to drop.
5. Ketogenic Diets Are a Proven Nutrition Intervention For Epilepsy
Given the recent media publicity, you would be forgiven for believing the ketogenic diet is a "new" thing.
Interestingly, it has been around (in name) for more than a century, with its roots beginning in the 1920's. At this point, the ketogenic diet was being trialed as a dietary therapy for epilepsy in children.
Of course, the ketogenic diet has been around for much longer in real terms, and the diet was likely the default for much of the human race during the ice age.
Until recently, ketogenic diets were mostly known as a potential intervention for epilepsy, for which they are one of the default treatment options.
Systematic reviews examining the effectiveness of ketogenic diets for epilepsy are positive too.
Based on these studies, researchers show that a ketogenic diet achieves a 90% reduction in seizure occurrence after six months of treatment. Additionally, evidence supports the "cautious use" of the diet (18, 19).
However, levels of carbohydrate restriction required for ketogenic meals are something that young children need careful supervision with, due to the risk of initial side effects.
Some examples of keto meals can be seen in these recipes.
Anyone considering dietary therapy for epilepsy should always consult their doctor/health team.
Key Point: Ketogenic diets are an effective nutritional therapy for epilepsy.
6. Low Carb Diets Increase Satiety Levels and Help Suppress Appetite
In truth, this likely depends on the exact formulation of the diet and the overall food choices.
There are many theories about why low carb meals encourage satiety. For me, it is most likely due to the higher protein intake that is typical of low carbohydrate plans.
It is a well-established fact that protein is the most satiating macronutrient (1).
On this note, evidence shows that high-protein meals reduce post-meal concentrations of the hunger hormone known as ghrelin (22).
The improvements in appetite regulation of low-carb diets may also involve fiber; after protein, fibrous carbohydrate is the next most satiating.
For instance, low carb dieters restrict refined, digestible forms of carbohydrate such as sugar, flour, and starches, and have a higher intake of fibrous carbs from low-sugar fruit and vegetables.
Key Point: Randomized trials and systematic reviews demonstrate that low carb and ketogenic diets help to suppress appetite.
7. General Health Benefits of a Higher Protein Intake
As previously mentioned, low carb and keto diets are often higher in complete sources of protein from animal foods.
High-protein low-carb diets (sometimes known as LCHP) are very popular too.
While we briefly touched upon protein's potential impact on satiation, this macronutrient offers many other benefits too.
Key Point: Eating a larger proportion of high-protein foods can have many health benefits.
8. Low Carb and Keto Diets Help To Reduce Blood Pressure
In truth, it is likely that anything that can improve our overall lifestyle will have a beneficial effect on blood pressure.
For example; exercise, eating nutrient-dense foods, losing weight, good sleep and controlling stress are all important.
Most people believe that salt has the biggest impact on our blood pressure levels. Since health authorities continuously tell us to cut down on our salt intake, this is understandable.
For some people, cutting down on salt is probably the right advice. But salt is an essential nutrient, and too little salt can be just as harmful as too much.
Excessive amounts of carbohydrate are another thing that can raise our blood pressure too. Let's not exaggerate though; this doesn't mean we will get high blood pressure if we eat a carrot or potato!
However, chronic, excessive consumption of refined carbohydrate and sugar is a common cause of high blood pressure (26).
Therefore, cutting down on dietary carbohydrate is one way to reduce blood pressure.
Key Point: Low carb diets are one potential intervention for high blood pressure
9. Lower Carbohydrate Diets Help Normalize Blood Glucose and Insulin Levels
Perhaps the most notable benefit of cutting down on carbohydrate is the effect this has on glucose and insulin levels.
While glucose and insulin are part of a natural biological process and essential to our body, excessively high circulating levels can be harmful.
For one thing, chronically high insulin levels, known as hyperinsulinemia, vastly raise the risk for chronic diseases such as type 2 diabetes, cardiovascular disease, and even dementia.
Over recent years, low carbohydrate diets have proven to be a robust dietary intervention for type 2 diabetes patients for these very reasons; they work well at controlling blood glucose levels.
Key Point: Very low carb diets are effective at improving insulin sensitivity and reducing fasting blood-glucose levels.
10. Effective For Reducing Dangerous Visceral (Trunk Region) Fat
Not all body fat is the same.
A particularly dangerous type is one called 'visceral fat' which is deposited in the abdominal cavity.
This abdominal fat is also known as 'organ fat' because it surrounds our internal organs. Unknown to many, it is possible to have this fat without showing signs of obesity, which is a situation referred to as "skinny fat".
Countless studies show the danger of this type of visceral fat, and it has strong links to a variety of metabolic and vascular diseases, including cardiovascular disease, diabetes, and Alzheimer's (32).
One reason why visceral fat is so dangerous is that these fat cells produce a range of hormones and inflammatory cytokines. Unfortunately, these compounds can damage our health by negatively impacting insulin sensitivity, the liver, and various other organs (33, 34).
Interestingly, low carbohydrate diets seem especially useful for reducing visceral fat.
Low Carb vs. High Carb Studies On Visceral Fat Reduction
In one calorie-matched low-carbohydrate versus high-carbohydrate dietary intervention, the low-carb participants significantly reduced visceral fat levels. On the other hand, there was no change in the high-carb participants (35).
However, in another calorie-matched study, there were no differences in effectiveness between the high carbohydrate and low carbohydrate diet. This particular study used a high-carbohydrate diet that was very low in processed carbs, which likely explains the difference (36).
That said, the fact remains that lower carbohydrate diets restrict processed carbs, and so they are one of the best (but not only) ways to reduce visceral fat.
Key Point: A notable advantage of low carb diets is that they effectively reduce abdominal region visceral fat.
11. Improve all Five Symptoms of Metabolic Syndrome
Metabolic syndrome refers to the cluster of conditions that can substantially raise the risk of chronic diseases like diabetes and heart disease.
There are five major symptoms/conditions of metabolic syndrome, and they often occur at the same time.
As a result, individuals who suffer from three (or more) of these metabolic disorders are viewed as having metabolic syndrome.
The five definitions are (37);
As we have already seen throughout this article, in randomized trials and systematic reviews, low carb dietary interventions result in;
In short, low-carb and ketogenic diets are clinically proven for reversing symptoms of metabolic syndrome.
Key Point: One of the biggest benefits of low carb diets is that they improve markers of metabolic syndrome.
12. Potentially Beneficial For Sufferers of Alzheimer's Disease
Alzheimer's disease is a terrible, progressive chronic disease that attacks and slowly takes away the sufferer's memory.
In recent years, the metabolic theory of the disease -- often dubbed 'Type 3 diabetes' -- is increasingly an area of research.
A few studies over the past few years investigated this issue; for further reading, see here;
In a nutshell; the metabolic theory of Alzheimer's relates to the progressively worsening insulin sensitivity of our brain.
As the brain becomes resistant to the effects of insulin, it can no longer use glucose for fuel in an efficient manner.
The result? Oxidative stress and neuronal cell death (38).
Can Ketones Help An Insulin Resistant Brain?
If you are aware of how ketogenic diets (and ketosis) operate, then you will know what ketone bodies (ketones) are.
When our body cannot meet its energy needs from carbohydrate, it produces a type of fuel from fat that we call ketone bodies. As an alternative source of fuel, researchers have speculated on the potential to treat Alzheimer's using ketones.
One of the reasons behind this is that mild Alzheimer's disease impairs the brain's ability to utilize glucose, but it doesn't affect the brain's ability to use ketones.
There is sadly no known cure for Alzheimer's at this point, but a ketogenic diet may be a potential therapeutic intervention to help slow the disease's progress.
Despite the existence of a few small studies on ketones and cognitive improvement showing promise, much more research is needed in this area (39).
Key Point: Dietary-induced ketosis through a very low-carb diet may hold benefit for Alzheimer's sufferers, but more research is necessary.
13. Low Carb and Keto Diets Restrict Metabolically Harmful Foods
This one is a benefit of low carb diets, but it isn't exclusive to this particular way of eating.
What do whole-food, paleo, low-carb and plant-based vegan diets all have in common?
The answer: they restrict ultra-processed, energy-dense foods that harm our health in the amount we eat them.
Examples of such foods include sugar, industrial seed ("vegetable") oils, and ultra-processed flours.
Sadly but not surprisingly, a recent study showed that almost 60% of calories in the American diet come from these ultra-processed foods (40).
Any diet that replaces these foods with nutrient-dense options like meat, fish, fruit and vegetables will provide benefits.
Key Point: Like any diet that restricts ultra-processed foods, low carb diets have a higher ratio of healthy, nutrient-dense foods.
14. May Have a Positive Effect On LDL "Cholesterol"
For a long time, researchers and the public alike have viewed low-density lipoprotein (LDL) as a harmful marker of cardiovascular risk that we need to reduce.
However, in recent years, science is suggesting that the topic is a lot more nuanced than merely LDL being "bad" and HDL being "good".
On this note, one area of research involves the differences in particle sizes of LDL;
Given the right conditions, any type of LDL may be atherogenic.
However, many researchers believe that the small and dense particles are more closely related to pro-inflammatory conditions. As a result, they believe these smaller particles are a greater cardiovascular concern than the larger LDL particles.
Some recent research findings on LDL particle size
Low Carb Diets and LDL Particle Size
On the other hand, high dietary intake of carbohydrate appears to increase the number of 'pattern B' small and dense particles (46).
It is worth noting that this doesn't mean all carbohydrates are bad.
These are correlations, and there is no controlling of dietary choices.
For instance, it is likely that individuals with higher carb intake are eating more refined carbohydrates and sugar, which are associated with higher triglyceride levels and phenotype B LDL.
Key Point: Diets with low to moderate carbohydrate intake correlate with the presence of larger, less atherogenic LDL particles.
15. Low Carb Diets Reduce Systemic Inflammation in Intervention Studies
Inflammation is one of the primary drivers of many chronic diseases, and it is believed to play a part in the etiology of cancer, diabetes, and cardiovascular disease (47).
Based on randomized trials featuring low-carbohydrate dietary interventions, there are a few notable findings on inflammatory markers.
For instance, compared to a "conventional" diet, participants in a 6-month dietary intervention experienced greater decreases in C-reactive protein levels on a low-carbohydrate diet. This difference was independent of weight loss (50).
In another randomized trial in participants with type 2 diabetes, well-devised low-carb diets and low-fat diets had a similar effect on weight loss.
However, the levels of inflammatory markers interleukin 1 and 6 (IL-1 and IL-6) were "significantly lower" in the low-carb group after 6 months (51).
Key Point: Well-formulated low carbohydrate interventions work well as an anti-inflammatory diet.
16. Kill Sugar Cravings and Improve Unhealthy Eating Behaviors
Many people find it hard to give up sugary foods, and the combination of fat and sugar is especially notable for encouraging over-consumption of food.
For instance; pizza, donuts, milk chocolate, and fried chicken are all good examples of these highly palatable foods.
Animal research suggests that continuously eating this kind of food creates a reward pathway in our brain that "eventually overrides the natural hormones that regulate food intake" (52).
Many people who have unhealthy relationships with food find that, once they adapt to a low-carb diet, these food cravings disappear.
This is simply because, by their very nature, low carb diets focus abstain from these foods that some people feel have "addictive" properties.
The restriction of these foods may be one reason why systematic reviews demonstrate that ketogenic diets are very satiating (53).
Another reason could be the tendency for low carb dieters to eat higher amounts of protein.
You can find some typical low carb recipes here.
Key Point: A large proportion of people find low-carbohydrate diets encourage satiation and reduce food cravings. Better eating behaviors lead to a wide range of health benefits.
17. Mood Improvements and Better Psychological Outcomes
Another interesting health benefit of low carb and ketogenic diets is the positive effect they appear to have on mood.
A recent systematic review featuring eight well-designed randomized trials had encouraging findings on this issue.
These studies examined the effect of low-carb diets as a potential treatment option for depression and anxiety. The results showed that lowering dietary carbohydrate intake had mood-enhancing benefits on self-esteem, anxiety, and depression (54).
Whether carbohydrate was replaced by protein or fat made no difference to the benefits, indicating that it was the lower carbohydrate intake that was responsible.
However, it is worth noting that none of the studies controlled for carbohydrate quality. In other words; before the dietary interventions, the participants were likely eating standard American diets full of refined carbohydrate.
If the studies had tested a diet that included more nutrient-dense sources of carbohydrate, it could potentially have had the same beneficial effect as lowering total carbs.
Regardless, the study showed that low carb interventions benefit mental health.
Key Point: Participants on low-carb dietary interventions for anxiety and depression all showed mood improvements.
18. Very Low Carbohydrate Diets Can Reverse Non-Alcoholic Fatty Liver Disease (NAFLD)
Fatty liver disease is a dangerous and very harmful condition characterized by a buildup of fat in the liver.
Excessive amounts of dietary carbohydrate are implicated as a cause of non-alcoholic fatty liver disease.
In fact, if you have ever heard of 'Foie Gras' --- a fatty duck liver that is considered a French delicacy --- then you may know that the English translation is literally 'fatty liver'.
To make this food, producers intentionally force-feed ducks with huge amounts of grains and sugar to cause the animals to develop fatty liver disease.
It is the same in humans too; prolonged over-consumption of carbohydrate leads to fatty liver disease (55).
One of the most proven health benefits of low carb diets is their effect on reversing this condition.
Numerous research studies have been undertaken in this area, and the evidence is quite clear that various calorie-restricted approaches can work well.
Key Point: Low carbohydrate diets benefit the health of NAFLD sufferers; research shows that reducing carbs can help to reverse the condition.
19. Effective Dietary Option For Some Cases of IBS
Irritable bowel syndrome (IBS) is an increasingly common condition that many people struggle with.
Abdominal pain, bloating, constipation/diarrhea and gas are all symptoms that characterize the condition.
While the cause of IBS remains unknown, there are various ways to manage the condition.
A very-low-carbohydrate intervention has been shown to improve all measurable quality-of-life factors related to IBS.
More specifically, a recent study demonstrated that very-low-carb (<20 g/carbohydrate per day) diets reduce abdominal pain, improve regularity, and "provide adequate relief" for IBS patients (59).
Key Point: Low carb diets can be an effective way to manage IBS symptoms.
Take Away Points
As shown throughout this article, low carbohydrate diets have many evidence-based health benefits.
However, there are two things to bear in mind;
Firstly; low to moderate carbohydrate consumption can be a healthy choice for the majority of people, but ketogenic diets are not the right fit for everyone.
While keto diets can be perfectly healthy, they do require research due to the possibility of initial side effects, and may not be the right fit for all.
Secondly; most of the low-carb and keto diets used as evidence for these health benefits were predominantly whole-food based varied diets.
Diets can be healthy or unhealthy depending on the formulation, and nutrient-dense whole foods should be emphasized rather than isolated fat.
Other than that, well-formulated low carb and ketogenic diets offer a range of health benefits.