People are always arguing over which diet is the best.
However, the simple truth is that humans can subsist on a range of different foods.
Overall, good health largely depends on the overall composition and nutrient-density of the diet.
That said, many people find that a low carb diet can be an excellent tool for improving health.
This article will look at what a low carb diet is, how to formulate it healthily, and some potential benefits and drawbacks.
What is a Low-Carb Diet?
A low-carb diet is defined as a way of eating that restricts carbohydrate to a very low level.
For example, the carbohydrate range could be anywhere between 0g and around 100 grams per day.
Low carb diets typically include moderate to high amounts of protein and fat, but the source of this fat is important.
For example, there is a significant difference between extra virgin olive oil and margarine, and whole food sources of fat are preferable.
Strict low carb diets are known as ‘ketogenic diets,’ and keto plans typically contain fewer than 50 grams of carbohydrate.
There is no right amount of carbohydrate for everyone, and some people may prefer a diet slightly higher in carbs, while others might prefer a minimal intake.
Should anyone feel confused about how to reduce carbohydrate intake, see this guide on easy ways to cut carb intake.
What Foods Are Low Carb?
Technically speaking, any food can fit into a low-carb diet.
The reason for this is because it is the total amount of carbohydrate that counts, and minimal amounts of high-carb foods can still be part of a low carb diet.
However, it is better to focus on more substantial amounts of some of the following low-carb foods.
Meat, Fish, Dairy, and Animal Fat
Meat, organ meats, and seafood are some of the most nutrient-dense foods in existence and provide a complete source of protein.
Dairy products such as cheese and milk are also nutritious options that can fit into a low carb plan.
Here are some low carb-friendly food choices from this category;
Among these foods, it is important to ensure a sufficient intake of omega-3, which is associated with better overall health, and a reduced risk of disease.
Focusing on getting at least 2-3 portions of oily fish per week is an excellent way to do this.
Some of the best oily fish options include anchovies, herring, mackerel, salmon, sardines, and trout.
Note: if you have a tight budget, see this guide to low carb eating on a budget.
Plant Foods and Plant-Based Oils
There is a bit of a myth that low carb diets are low in fruits and vegetables, but this isn’t the case.
A wide range of fruit and vegetables are low in carbohydrate, and aside from high-sugar fruits and potatoes, most plant foods are low carb friendly.
Additionally, other plant foods like nuts and certain cooking oils can all play a healthy part in the diet.
Here are some good examples of plant foods suitable for a low carb diet;
|Beets||Bell pepper||Berries (all)|
For the most part, it is better not to worry about the carbohydrate content of green vegetables as they are full of beneficial nutrients and fiber. As a result, they contribute very little in the way of “net” (digestible) carbs.
Starchy vegetables such as potatoes, parsnips, and sweet potatoes can also fit into a low-carb diet.
However, these should be eaten in moderation or not at all (depending on how low-carb you want to be).
Additionally, fermented vegetables are another healthy choice, and foods like kimchi, sauerkraut, and pickled vegetables are all excellent options.
For more low carb food ideas, see this shopping list for a detailed guide.
Snacks don’t have to be unhealthy, and numerous options can fit into a low carb diet.
The following ideas are all low in carbs and free of unhealthy oils;
|Cherry tomatoes||Dark chocolate *||Jerky|
|Macadamia nuts||Pecans||Pork rinds|
*Ideally 80% cocoa or above
For 38 low carb snack ideas and recipes, see this list here.
While sticking to nutritious meals is better than constantly snacking, the above foods are all better options than things like potato chips and candy.
Water is always the healthiest option, but the following drinks are all compatible with low carb diets;
|Black tea||Coffee||Green tea|
|Herbal/fruit tea||Milk (in moderation)||Water|
For a guide to every almost every common drink alongside their full carb counts, see this low carb drinks guide.
For those who enjoy the occasional alcoholic drink, you’ll be glad to know that some alcohol options are low carb-friendly.
See this guide to the best low carb alcohol options for a full review.
Foods To Limit/Avoid
This is true for all diets rather than just low-carb, but it is always better to limit the consumption of ultra-processed foods.
These packaged foods usually contain a mix of flour, sugar, and oils and provide very little in the way of essential nutrients.
Additionally, since this is a low-carb diet we’re talking about, this means that foods containing high levels of carbohydrate are not compatible.
These foods include:
- Bread and other refined grains
- Crisps/potato chips
- Fast food (most)
- Fruit juice
- Soda and other sugary drinks
For some reasonably healthy fast food options, see this guide here.
What Can You Eat On a Low Carb Diet?
To provide an idea of some potential low carb meals, here are some ideas for breakfast, lunch, and dinner.
- Bacon and eggs with mushrooms and sauteed chives
- Kippers or sardines with leafy greens
- Cheese and onion omelet fried in butter
- Steak, onions, and mushrooms
- Yogurt, mixed nuts, and berries
- A crustless cheese and vegetable quiche (or frittata)
- Scrambled eggs, some smoked salmon, and an assortment of vegetables
For those who are out of the house during weekdays, here are some packable on-the-go lunch options.
- A piece of cheese, a handful of nuts, some berries, and an avocado
- Chunks of chicken in a leafy green salad with cherry tomatoes, balsamic vinegar, and extra virgin olive oil
- Four hard-boiled eggs, a cup of fresh berries, and some heavy cream
- Greek yogurt mixed with pieces of dark chocolate, blueberries, and mixed nuts
- Salmon sashimi salad: pieces of raw fish in a colorful salad, mixed with tamari soy sauce and a squeeze of fresh lemon
- A glass of whole milk, a handful of almonds, and an apple
- Ricotta cheese, sliced tomato, and leafy greens drizzled with olive oil and balsamic vinegar
Here are some easy to make home-cooked dinner options;
- Steak, mushrooms, and an assortment of sauteed vegetables
- Fillet of salmon in a coconut cream sauce, with chives, leeks, and onions
- Baked mackerel, steamed leafy greens, a sweet potato, and dark chocolate for dessert
- A large pork chop with butter sauce served alongside your favorite vegetables
- Liver and onions – a traditional class, but one of the most nutritious meals you can eat
- Homemade burgers made with 100% ground meat and your choice of seasonings – serve with a side salad
- Beef ribs marinated in tamari, garlic, ginger, and olive oil – serve with mushrooms and a variety of vegetables
Depending on your goals, eating these kinds of meal—high in protein and fiber—often improve satiety, which can lead to weight loss.
In contrast, gaining weight on low carb is also very possible, and it is merely a matter of increasing calories and eating more.
For some more examples of low carb recipes, see these 30 healthy and simple meal ideas.
Potential Benefits of a Low Carb Diet
1. Low Carb Diets Are Clinically Proven For Weight Loss
Many people find that low carb diets work exceptionally well for losing weight.
Firstly, this depends on both adherence and the diet being well-formulated.
However, a lot of people find that low carb diets increase satiety levels and reduce overall food intake.
One reason for this could be that low carb dieters often have a higher protein intake, recognized as being the most satiating macronutrient (1).
Additionally, the diet restricts foods that people typically “crave” (the carbohydrate-fat combinations of donuts, pizza, and so on). For many people, abstaining from these foods is easier than eating them in moderation.
Systematic Reviews (Slightly) 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.
2. Can Help Manage Type 2 Diabetes
Low carb and ketogenic diets are a popular nutrition intervention for those with type 2 diabetes.
Notably, one of the most significant merits of these 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 support and 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.
3. Low Carb Diets Tend To Increase HDL (“Good Cholesterol”) Levels
High-density lipoprotein (HDL), commonly known as “good cholesterol,” is associated with a reduced risk of cardiovascular problems (10).
Numerous studies have examined the effect of low-carbohydrate diets on HDL levels.
Based on current science, in isolation, this rise in HDL should be a protective factor against cardiovascular risk.
However, this does depend on how the diet affects other markers of health too.
4. Reductions in Triglyceride Levels
Triglycerides are a storage form of fat, and they have a relationship with overconsumption of 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).
This is notable because some cardiovascular researchers believe that the triglyceride to HDL ratio is one of the most reliable markers of cardiovascular risk (17).
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, the diet has been around for more than a century, with its roots going back to the 1920s. At this point, the ketogenic diet was trialed as a dietary therapy for epilepsy in children.
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.
Anyone considering dietary therapy for epilepsy should always consult their doctor/health team.
6. Low Carb Diets May Increase Satiety Levels and Help Suppress Appetite
In truth, this likely depends on the exact formulation of the diet and the overall food choices.
For one thing, it is a well-established fact that protein is the most satiating macronutrient (22).
On this note, evidence shows that high-protein meals reduce post-meal concentrations of the hunger hormone known as ghrelin (23).
The improvements in appetite regulation of low-carb diets may also involve fiber; after protein, fibrous carbohydrate is the next most satiating.
On the positive side, low carb diets typically restrict refined carbohydrates such as sugar, flour, and starches, and have a higher intake of fibrous carbs from low-sugar fruit and vegetables.
You can see some examples in these low carb recipes.
7. General Health Benefits of a Higher Protein Intake
As previously mentioned, low carb diets often contain more complete sources of protein from animal foods.
- Greater lean body mass.
- Better appetite regulation and decreased food cravings.
- Helps with gaining muscle.
- Protects bone and muscle health, particularly as we age and the rate of muscle-protein synthesis drops.
- Essential for the growth and repair of all our body’s cells.
- Plays a vital role in the production of enzymes and hormones.
8. May 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 habits, and controlling stress are all important.
Most people believe that salt has the biggest impact on our blood pressure levels. Since we continuously hear messages in the media to cut down on our salt intake, this is understandable.
For some people, cutting down on salt is probably the right advice.
However, chronic, excessive consumption of refined carbohydrate and sugar is a common cause of high blood pressure (27).
9. Lower Carbohydrate Diets May Help To 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.
Regarding cardiovascular risk, studies demonstrate that the risk increases in a dose-dependent manner.
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 for controlling blood glucose levels.
10. May 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 health markers are viewed as having metabolic syndrome.
The five definitions are (34);
- A large waist circumference (>102 cm)
- High triglyceride levels (>1.69 mmol/l or >150 mg/dL)
- Low levels of HDL (<1.04 mmol/l or <41 mg/dL)
- High blood pressure (>130 mmHg)
- Elevated fasting blood glucose (>5.6 mmol/l)
As we have already seen throughout this article, in randomized trials and systematic reviews, low carb dietary interventions result in;
- Weight loss
- Reductions in triglyceride levels
- Increased levels of HDL
- Reduced blood pressure
- Better control of blood glucose levels
In short, well-implemented low-carb and ketogenic diets are clinically proven for reversing symptoms of metabolic syndrome.
11. Potentially Beneficial For People Living With Alzheimer’s Disease
Alzheimer’s disease is a terrible, progressive chronic disease that attacks and slowly takes away the patient’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 resistance in the brain.
The idea is that if 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 (35).
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, a biochemical process called ketogenesis starts.
Through this process, our body produces a type of fuel from fat that we call ketone bodies.
Since it is an alternative source of fuel, researchers have speculated on the potential to treat Alzheimer’s using these 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, this area requires much more research (36).
12. Low Carb Diets Typically Emphasize Whole Foods
This one is a benefit of low carb diets, but it isn’t exclusive to this particular way of eating.
For instance; 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 (currently) eat them.
Examples of such foods include sugar, 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 (37).
Any diet that replaces these foods with low-carb foods like meat, fish, fruit, and vegetables will provide benefits.
For anyone struggling to cut out sweet-tasting foods, these sweeteners can be a good replacement option for sugar.
Potential Drawbacks of a Low Carb Diet
1. Effect On LDL Cholesterol
First of all, low carb diets—particularly when higher in saturated fat—can raise levels of LDL cholesterol in some individuals.
In a recent randomized controlled trial of 30 healthy participants, each person experienced a rise in LDL cholesterol of between 5% and 107% (38).
However, it should be noted that this is not always the case.
For example, a systematic review of eight randomized trials—featuring over 800 participants on a low carb diet—showed contrasting results.
In this study, carbohydrate-restricted diets resulted in no significant changes to LDL cholesterol levels after 6, 12, and 24 months (39).
This suggests that the rise in LDL is dependent upon the formulation of the diet, and probably a result of diets that emphasize more substantial amounts of saturated fat.
That said, there is no conclusive evidence that dietary saturated fat intake raises the risk of cardiovascular disease.
In a meta-analysis of 21 studies featuring 5-23 years of follow-up of nearly 350,000 participants, saturated fat intake had no association with an increased risk of cardiovascular disease (40).
Is LDL a Problem?
First of all, there are clear associations between higher levels of LDL-C and cardiovascular disease (41).
However, correlation does not necessarily equal causation.
Additionally, in recent years, research has suggested that the topic may be more nuanced than LDL being “bad” and HDL being “good.”
On this note, one area of research involves the differences in particle sizes of LDL;
- Phenotype A: large, buoyant LDL particles (>25.5 nm)
- Phenotype B: small, dense LDL particles (<25.5 nm)
Some recent research findings on LDL particle size
- In 520 patients with angina symptoms and suspected cardiovascular disease, systemic inflammation was closely related to small LDL cholesterol counts. However, there was no relationship between mean LDL cholesterol and inflammatory markers (42).
- In 11,419 men and women, small-density LDL levels “were strongly correlated” with cardiovascular heart disease. Interestingly, this link was strong even in individuals with “low risk” based on their total LDL count (43).
- Small dense LDL particles are more susceptible to oxidation and more likely to penetrate the arterial walls (44).
Low Carb Diets and LDL Particle Size
On the other hand, excessive dietary intake of carbohydrate appears to increase the number of ‘pattern B’ small and dense particles (47).
There are also some cardiovascular researchers who believe that hyperinsulinemia—chronic high levels of fasting insulin—are a more significant cardiovascular risk factor than LDL.
On this note, a meta-analysis of 22 studies featuring over 80,000 participants found that hyperinsulinemia was “significantly associated with an increased risk of coronary heart disease” (48).
Summary: Low Carb Diets May Increase LDL Cholesterol Levels
All in all, it is possible that low-carb diets may increase LDL levels (as well as increasing HDL).
Since even cardiovascular researchers disagree on the precise cause of cardiovascular disease, this is something I am hesitant to speculate on.
However, for those that feel this is a concern, it may be worth;
- Limiting the intake of isolated saturated fats such as butter and coconut oil.
- Ordering a full lipid panel (cholesterol test) after 1-2 months on the diet to analyze any possible changes. Having a health check on any new diet is a sensible precaution, as different diets can affect us all in different ways.
2. Some People Find Low Carb Diets Hard To Stick To
Bacon, beef, cheese, dark chocolate, and salmon… most carnivores and omnivores would be happy with any of these foods on their plate.
However, some people still find it hard to restrict higher carbohydrate foods.
In nutrition trials, it is rare for a study to have full compliance, and it is no different for low-carb diets.
For example, in a recent 12-month clinical trial 148 adults were assigned to a diet with a daily carbohydrate intake of <40 grams.
After three months, the compliance rate was 74%. However, this fell to 60% after six months and dropped further to 45% at the 12-month mark (49).
A meta-analysis of 12 studies featuring 270 patients looked at compliance rates for various low carb and ketogenic diets. The average compliance rate across all studies was 45% (50).
This does not mean that low-carb diets are particularly difficult to adhere to, and poor compliance is a common feature of studies on all kinds of diet.
However, it does show that the diet may be hard to stick to for people who;
- Don’t enjoy the way of eating
- Require help/education and don’t have the necessary support
As shown throughout this article, low carbohydrate diets can have many evidence-based health benefits.
However, they may not be the right match for everybody.
Like all ways of eating, low carb diets can be either healthy or unhealthy depending on the formulation, and it is best to focus on nutrient-dense whole foods rather than isolated fat.
If you have any questions, check the low carb FAQ to see if the answer is there.
There are also some low carb myths to be aware of.
If you need more help with low carb, then this A-Z resource contains lots of educational resources.
What are the major differences between low carb and ketogenic diets? See this summary.