Low carb alcohol may be consumed while on the keto diet, such as spirits and low carb cocktails.
The keto diet is a low carbohydrate diet that has been helpful for many people trying to lose weight[1].
But where does alcohol fit into this?
Table of contents
Introduction
In our article about what to eat on the keto diet, we outlined which foods should be consumed to get a healthy balance of fats, proteins and carbohydrates[1].
However, you may have noticed that alcohol was missing from this article. Why? Well, because we generally do not recommend alcohol consumption, due to the potential negative health effects.
This article will not focus on the health risks of alcohol, but it is important to mention that alcohol does indeed pose a health risk[2].
There is extensive literature documenting the negative health effects of alcohol consumption[2].
This includes the development of chronic diseases such as liver disease, dementia and certain cancers[2].
But we understand that sometimes people like to indulge in alcohol. Depending on where you are from, alcohol consumption may be a large part of what fuels socialisation. So it’s natural to think about how alcohol fits into the keto diet.
So how does alcohol impact ketosis and should you consume it while on the keto diet? Let’s find out.
Understanding alcohol on the keto diet
What is alcohol?
The first question you might be asking is, what is alcohol? Alcohol is ubiquitous but people are often unaware of the nature of the compound.
From a chemical perspective, alcohols are organic compounds, characterised by an -OH (hydroxyl) functional group bound to a saturated carbon atom. The type of alcohol then varies depending on the number of carbon atoms the compound contains[3][4].
Ethanol is an alcohol consisting of 2 carbon atoms, which is a psychoactive compound, and leads to a state of drunkenness if consumed in excess. Drinking alcohol (e.g. beer, spirits etc) consists of the chemical alcohol, ethanol[3][4][5].
Basically, there is the chemical alcohol (e.g. ethanol) and then the drinking alcohol (e.g. beer), which contains ethanol.
What type of calories does it contain?
Alcohol is a separate class of macronutrient and is not a carbohydrate.
As you may have read in our article about food choices on the keto diet, there are 3 major macronutrients; proteins, fats and carbohydrates.
Alcohol on the other hand, is a compound outside of this trio. It is often referred to as ‘empty calories’ as it contains caloric value, without serving any specific nutritional purpose. In addition, it is also devoid of vitamins and minerals[6].
Alcohol contains 7kcal per gram, compared to 4kcal per gram for proteins and carbohydrates. It only contains less calories per gram than fat, which contains 9kcal per gram[6].
Although alcohol itself isn’t a carbohydrate, many alcoholic beverages (e.g. beer and cocktails) contain a large number of carbohydrates. As a result, these drinks are not suitable for the keto diet.
How is it metabolised in the body
Alcohol is metabolised through the action of several enzymes and primarily occurs in the liver.
When alcohol is consumed, alcohol dehydrogenase enzymes in the liver breakdown the alcohol. This results in the oxidation of ethanol to acetaldehyde[6][7].
When very large volumes of alcohol are consumed, additional enzymes such as cytochrome P450 and catalase are also utilised to convert ethanol to acetaldehyde[6][7]. Acetaldehyde is a carcinogen and causes tissue toxicity. As a result, it must be broken down quickly[7].
Acetaldehyde is then converted to acetate through the action of aldehyde dehydrogenase enzymes[6][7].
The product of this reaction, acetate, is subsequently converted to acetyl-CoA, which enters the citric acid cycle. Here, it is oxidised to release ATP, which can be utilised by various cells in the body[6][7][8].
In addition, this ATP can be utilised to convert acetyl-CoA to fatty acids, which can then be stored in case of excess requirement[8][9].
Does alcohol impact ketosis?
Alcohol could slow ketosis, due to preferential metabolism
The keto diet is characterised by carbohydrate restriction and entering a state of ketosis. So a key question is “does alcohol impact ketosis?”
The answer is somewhat complex, and is related to how alcohol is metabolised in the body.
As mentioned, alcohol is toxic in the body. Furthermore, the temporary by-products of alcohol breakdown, namely acetaldehyde, are even more toxic. Consequently, the body needs to break down alcohol as quickly as possible to avoid harmful effects, due to toxicity[6][7].
In order to mitigate this toxicity, the body preferentially oxidises and metabolises alcohol, compared to other macronutrients[6].
So by following a keto diet, you are primarily metabolising fatty acids to induce ketosis. However, when you drink alcohol, the body switches to preferentially metabolising alcohol[6][7].
As a result, you could conclude that drinking alcohol temporarily stalls ketosis.
This is because the body cannot switch back to utilising energy from ketone bodies until all the alcohol and by-products have been broken down[7].
When consumed in moderation, alcohol has a minor impact on ketosis
However, it appears that alcohol intake doesn’t significantly impact ketosis[10].
Studies assessing alcohol intake in combination with a high-fat diet have shown an increase in ketone bodies in the blood and urine[10].
So once the alcohol is broken down, you can readily re-enter a state of ketosis.
It’s therefore fair to say that alcohol may impact ketosis, but not to the same degree as consuming large amounts of carbohydrates.
What effect does alcohol have on insulin and blood glucose?
Alcohol likely has minimal impacts on fasting blood glucose
There are a number of studies that have assessed the impact of alcohol consumption on fasting blood glucose levels. The results are fairly consistent, and demonstrate that acute alcohol consumption does not impact fasting blood glucose[11][12].
This was the conclusion of a meta-analysis of 14 interventional studies. It has also be noted that alcohol consumption while fasted can result in hypoglycemia (very low blood sugar)[11][13].
This is because alcohol inhibits both gluconeogenesis and glycogenolysis[13].
However, this is different in cases of simultaneous carbohydrate intake. If alcohol is consumed in combination with a high-carbohydrate meal, this can result in a transient increase in blood glucose[12][14].
This is because alcohol is preferentially metabolised, leading to rising blood glucose levels. In healthy individuals, insulin will be secreted to counteract the blood glucose rise. However, this could be a concern for diabetics, who are unable to produce sufficient quantities of insulin[12][14].
The results surrounding glucose tolerance can be conflicting but overall, alcohol seems to have a minimal impact on blood glucose.
Alcohol does not impact fasting insulin, and could improve insulin sensitivity
Light to moderate alcohol consumption can result in improved insulin sensitivity.
The evidence suggests that alcohol consumption should not impact blood glucose, but what about insulin?
In general, the literature demonstrates that light to moderate alcohol consumption results in improved insulin sensitivity[15].
For example, a systematic review and meta-analysis found that moderate alcohol consumption was associated with reduced fasting insulin levels in non-diabetic patients[11].
Further, a retrospective cohort study examining 280,194 people found that alcohol consumption was associated with improved markers of insulin resistance[16].
Moderate intake of alcoholic beverages is associated with a lower incidence of diabetes
Interestingly, studies have also found that there is a lower incidence of diabetes in moderate alcohol consumers in the general population. This may be due to the fact that alcohol improves insulin sensitivity[15].
The impact of alcohol consumption on the incidence of diabetes was further examined in a study conducted on individuals in a diabetes prevention programme. These individuals were included in the programme as they were identified as being ‘high risk’ for diabetes[16].
The study found that those consuming moderate amounts of alcohol showed a reduced risk of diabetes, and improved insulin sensitivity[16].
These studies highlight that moderate alcohol consumption does not detrimentally impact insulin sensitivity and secretion. In fact, moderate alcohol consumption improves insulin sensitivity, and therefore should not be a major concern on the keto diet[15][16][17].
Can you drink alcohol on the keto diet?
Taking all the evidence into account, consuming moderate amounts of alcohol on the keto diet is acceptable.
Moderate intake of alcohol does not significantly impair ketosis, or negatively impact blood glucose or insulin. As a result, consuming alcohol in moderation should be compatible with the keto diet[10][15][16][17].
However, this is only from a purely ketogenic perspective. It is not advisable to regularly consume alcohol, as it is associated with numerous detrimental impacts on your health. This includes and increased risk of different cancers and neurodegenerative diseases[18].
The Dietary Guidelines for Americans recommends that you should limit yourself to no more than 2 drinks per day for men and 1 drink per day for women, on days when alcohol is consumed.
Similarly, in the UK, the NHS recommends no more than 14 units per week. This is around 6 medium glasses of wine, or 6 beers (ABV 4%).
Should you consume alcohol on keto?
As we have outlined, moderate alcohol consumption can be compatible with the keto diet.
However, should you drink on the keto diet?
This is quite a personal choice, and ultimately depends on your health and wellness priorities. As mentioned in our article about food choices on the keto diet, it is important to choose a diet full of healthy whole keto foods.
In our opinion, alcohol has numerous negative impacts which outweigh the positives. As a result, we would not advise consuming alcohol on a regular basis.
But does that mean you should give it up all together?
Not necessarily. Occasionally enjoying alcoholic beverages can be a good approach on the keto diet (for example, having 1 or 2 drinks once per week).
In fact, occasional alcohol intake may improve insulin sensitivity. Remember to moderate your intake, and ensure you are not drinking too frequently[15].
Read more about the WHO report on alcohol consumption.
You can also find information here if you are struggling with alcohol abuse.
What type of alcoholic beverages are best on keto?
Now that we have settled whether alcohol can be consumed on the keto diet (yes it can), let’s take a quick look at what options are best.
Although ethanol (a chemical alcohol) does not contain any carbs, different forms of alcoholic beverages contain various amounts of carbs[6].
Alcoholic drinks such as beer contain quite a large number of carbohydrates. This is due to the high amount of hops, barley and wheat. Try looking for light beer alternatives, which contain significantly fewer carbohydrates[19].
Other drinks to watch out for are cocktails. Cocktails frequently contain high-sugar mixers, which will spike your insulin, increase your calorie intake, and could knock you out of ketosis.
Studies have even found that sugar can potentiate drinking in adolescents, and could impact neurochemical and biological mechanisms that increase alcohol consumption[20].
Instead, try cocktails with low sugar content, such as those made with sugar-free mixers.
Remember, when consuming alcohol, it is important to moderate your intake.
To minimise the number of carbs from alcohol, we recommend focussing on spirts like vodka, and some wines.
Check out our full guide on the best alcohol options on the keto diet.
Alternatives to alcohol include sugar-free soft drinks, as well as alcohol-free beverages. Remember to check the carbohydrate and sugar content to ensure you are not accidently overconsuming carbs.
Wrapping up
Alcohol, when consumed in moderation, can be included in the keto diet.
Understanding which alcohol to drink on the keto diet is important to set yourself up for success. Focussing on sugar-free options, and avoid alcoholic beverages with naturally high quantities of carbohydrates.
It is also important to be aware that alcohol has a number of harmful health effects. As a result, please ensure you drink alcohol in moderation, and choose alcohol-free options where possible.
If you want to learn more about what alcoholic drinks you should consume on the keto diet, read on for a more detailed guide.
As always, it is recommended to consult with a medical professional before making significant changes to your diet.
