Do you want to lose weight, boost your metabolism, improve your digestion, detox your body, have glowing skin and all while keeping your body nicely alkalised and in balance? You can. All you need do is start the day with a glass of water with the juice of a freshly squeezed lemon added. I mean, water is good for you? And lemons, being a fruit, are good for you? So why not combine the two and get a quantum level of health-boosting synergy! Okay, now for a dose of reality as I explore the whole lemon water trend and pull apart those amazing health claims to see what is hype and what is reality.
Lemon water is all the rage these days. A quick search of the Internet finds no shortage of glowing health reports claiming how it can improve digestion, rid the body of toxins, boost weight loss, turbo-charge your immune system and balance the body’s pH. Oh, and it’s also great for your skin. Sign me up.
So what is lemon water? It’s simply the juice of a lemon added to hot or cold water and usually drunk on an empty stomach first thing in the morning. Some people may add a few additional ingredients like honey, mint, turmeric or cayenne pepper, but it is the lemon water that is the base drink and that’s what I’ll focus on for this blog post.
What’s in your lemon?
Let’s dive straight into all of the nutritional goodness you get in your glass of lemon water. If you used a very generous squeeze of lemon (let’s call it 50 mL of juice), then you’ll be getting about 40 kilojoules (10 Calories) and about 20 milligrams of vitamin C. That quantity of vitamin C is a bit under half the recommended daily amount for an adult if you use Australian and New Zealand recommendations and about a third of daily requirements if you use US recommendations. So not an insignificant amount of vitamin C to be sure.
Vitamin C has many important roles in the body. One of those is its essential role in the production of collagen. Collagen is responsible for the elasticity and strength of skin and this is why some of the signs and symptoms of scurvy relate to bleeding gums, poor wound healing and bruising.
Fun fact: over 250 years ago (and well before vitamin C was characterised and named as a vitamin), it was the British physician James Lind who all but eradicated the terrible disease scurvy which was rampant among British sailors on long sea voyages caused by the lack of vitamin C from fresh foods in their diet. He did this through controlled experiments to finally settle on the juice of lemons or limes as the key food to restore them to health and prevent scurvy from occurring in the first place.
So yep, if you’re at risk of scurvy, then lemon water will certainly be of huge benefit. Of course, any citrus fruit will give you loads of vitamin C. Eating an orange or kiwi fruit in fact would give you four–times the amount compared to your lemon water. And foods like broccoli, tomatoes, red capsicum and a whole bunch of others are also great sources.
So if you’re relying on mainly lemon water to get your vitamin C for the day for months on end then you’ve got some serious problems going on with your diet and lifestyle. Maybe get that sorted first.
After vitamin C though, it is a fail as far as the nutritional profile goes for lemon water for getting close to any other of your nutrient needs apart from the biggest one of all: water.
Water, water everywhere
So let’s look at water. If you’re struggling to get enough water each day, then lemon water will certainly help. And if the citrus tang encourages you to drink more, then that isn’t such a bad thing. Especially if you are replacing soft drinks, sports drinks and even fruit juices with lemon water – that’s a lot less sugar and calories you’ll be having in your diet.
Swapping out sugary drinks for lemon water will be better for your health, but so too would….plain water. But if you prefer lemon water, then I’m certainly not going to knock it for being a good source of water and a way to cut down on sugar in your diet.
Will you lose weight?
What about those weight loss claims attributed to lemon water? There’s nothing that special or outstanding about them because if you’re drinking lemon water in place of food or other liquids full of calories then that can be enough to kick-start weight loss.
When people increase their water consumption, especially before meals, and replace calorie-filled beverages with water, then at least in the short–term, it can result in a small amount of weight loss if the habit is maintained. A 2019 review on this topic found an average of 5% weight loss when using a mixture of increasing daily water intake, replacing caloric beverages with water, and having a pre-load of water before a meal.
But note how this research was all about water. Adding lemon to the water doesn’t make it any better or worse for increasing the rate of weight loss or ‘fat burning’.
So let’s call that two wins for lemon water so far: vitamin C and water. But neither property is owned by lemon water and their effects are well-and-truly overhyped when you consider all the other food sources of vitamin C in a person’s diet and how much water they drink over the day in food and beverages that aren’t lemon water.
Good for your digestion
One bit of intriguing research has profiled the effect of lemon juice on digestion when consumed at the same time as a meal containing starch. Here, it is the effect of all that lemony acidity that reduces the activity of an enzyme called alpha-amylase which is found in saliva in the mouth. Alpha-amylase is involved in the process of starch breakdown which starts in the mouth.
The effect of acidity on alpha-amylase translates to a lower glycaemic response when lemon juice is drunk with starch-containing food. This could have some relevance to people with diabetes.
But it doesn’t mean you won’t absorb any of the starch in food if you drink lemon water with a meal, only that it may take a bit longer to absorb.
Don’t get too excited though as there is nothing special about lemon juice. Similar effects have been seen with vinegar; be it apple cider vinegar or private label vinegar off the supermarket shelf – it all does the same thing because of its acidity.
So there could be some truth to the claims about lemon juice improving digestion, but the disclaimer here is that you need to drink it at the same time you are eating a meal containing starch. Contrast that with the typical advice about lemon water to do with starting your day with a glass of it to help with digestion. That will have zero effect on your digestion of food as most of the food you eat will be later in the day.
Does lemon water ‘boost your metabolism’?
What about those claims you read of lemon water ‘boosting your metabolism’? There are many pills, supplements and foods that claim to boost metabolism and burn fat. Most of these claims are unproven. Some substances such as caffeine and chilli do have a small effect on metabolic rate, but the effect is very small.
There is no plausible metabolic mechanism for why a glass of diluted lemon juice should do anything to your metabolism short of the tiny amount of energy that your body uses to digest, absorb and move that lemon water along your gut. That is called the thermic effect of food and it is the energy required to digest and assimilate food. It can differ depending on the macronutrient content of the meal with fat having an energy cost of about 5%, carbohydrates about 10% and protein around 25%.
Before you get too excited about all this thermic effect of food theory, you can’t ‘eat yourself thin’. Think of the thermic effect of food as an energy tax on food. But most of the energy in the food you will still make use of.
So considering the amount of energy in a glass of lemon water is tiny to start with, at just a few calories, then the thermic effect of food here is so small as to be effectively zero. But to be kind, let’s call it 1 Calorie for that glass of lemon juice. Ozempic it is not.
But does lemon water boost your energy? The answer is ‘probably’ but it would be from the placebo effect. If you are drinking lemon water because you felt it was good for you and you were all about carpe dieming each morning with your lemon water ritual, then you’ll be giving yourself a bit of positive reinforcement.
Kidney stones be gone
One area where there could just be some health benefits of lemon water relates to reducing the risk of recurrence of kidney stones. Kidney stones are hard deposits of minerals and acid salts that stick together in concentrated urine. They are quite common, and people who get them often get them repeatedly.
The citric acid found in lemons (and of course all other citrus fruits), may help reduce the risk of kidney stones recurring. It does this by binding to calcium in the urine which prevents crystal growth by creating a less favourable environment for kidney stone formation.
There is now even clinical trial evidence to support a benefit. A recent randomised-controlled trial published in 2022 that built on previous research, found that in 203 people with recurrent kidney stones who drank either 60 mL of fresh lemon juice twice per day or nothing at all, there were lower rates of kidney stone recurrence over two years in those drinking the lemon juice.
So there could just be something to this story of citric acid and kidney stones. There is even some mixed evidence that lemonade could do something similar. But again, it is the citric acid that is added to these types of drinks that is showing a benefit so please don’t use it as an excuse to down a litre of Sprite each day for your kidney health.
Alkalising your body: just say no to pseudoscientific nonsense
One claim made about lemon juice needs to be called out for the BS that it is: and that has to do with its alleged ‘alkalising’ effect on your body.
Alkaline diets have been promoted for years as a magical cure-all to treat or prevent cancer, heart disease, low energy levels and a whole host of other illnesses. The premise behind the whole alkaline trend is related to something called the acid-ash hypothesis.
It goes like this: when we eat certain foods like meat, poultry, cheese, fish, eggs, and grains, ash is produced in the body. The type of ash is determined by the relative content of acid-forming components in a food such as phosphate and sulphur, and alkali-forming compounds such as calcium, magnesium, and potassium. Most fruits and vegetables (and that includes lemons even though we think of them as an acid food) form alkali compounds in the body.
Where to start. As with any crazy diet idea, there is always a kernel of truth behind it. It is true that different foods produce different types of metabolic by-products. Alkaline ash is produced by fruits, vegetables, nuts and legumes. Neutral foods are more natural fats. And the ‘evil’ acid ash-producing foods are meat, poultry, fish, dairy, eggs, grains and alcohol.
But back to pH and why this diet is pseudoscientific nonsense. pH is, of course, a measure of acidity or alkalinity. The pH scale ranges from 1 to 14 with 1 being strongly acidic, 14 being strongly alkaline, and 7 neutral. Anything below 7 is acidic, and anything above 7 is alkaline (also known as basic).
Your stomach acid and battery acid have a pH of about 1, lemons a pH of 2, grapefruit about 3 and black coffee a 5 or 6. On the other end of the spectrum, seawater is about pH 8, peas are 9, spinach is about 10 and liquid drain cleaner has a pH of 14. I guess Draino would count as a health tonic supplement in the alkaline diet world then.
Advocates pushing the alkaline diet claim that since the normal pH of blood is slightly alkaline at 7.4, then you should eat alkaline foods and shun acidic foods to keep it there.
Here’s the thing: if food really could make an impact on blood pH in either an acidic or alkaline direction it would be life-threatening. A blood pH below 7.35 is called acidosis and above 7.45 it is alkalosis. Both are medical emergencies that can be fatal.
The body keeps blood pH in a very tight range thanks to the coordinated actions of the lungs and kidneys. But anyone who has studied physiology would know this sort of basic stuff. Those promoting an alkaline diet are not in that group.
Food though can change the pH of urine and that’s one of the regulatory mechanisms the body uses to buffer against too much acidity or alkalinity. Urine though is contained in the bladder so does not affect the pH of any other part of your body.
So, while an alkaline diet may change the pH level in the urine it has not been shown to cause a sustained change in blood pH levels. That’s because our natural acid-base regulatory mechanisms don’t need a special diet to work so any effect of food on blood pH is minimal and transient.
Even when those promoting alkaline diets defer to the fact that acidic foods don’t directly change blood pH, they have a backup argument ready to go. They say that acidic foods place stress on the body by requiring it to pull alkaline-rich minerals like calcium, phosphorus, and magnesium from the bones, teeth, and organs to buffer against the acidity. They allege this leads to osteoporosis and fatigue, and compromises our immune system, making us vulnerable to viruses and disease.
That claim just doesn’t hold pH 7 neutral water. Yes, that’s a great theory which if you want to apply to ‘acidic foods’ will apply equally to ‘alkaline foods’ so an all-alkaline diet would be just as harmful and ‘stressful’ from the need of the body to buffer the pH back into the tight range of 7.35-7.45.
And all this focus on blood pH pushed by alkaline diets ignores this one simple observation: pH differs throughout different body compartments. You want a very acidic stomach to help with efficient digestion. While your mouth salvia is slightly acidic at about pH 6 which is optimal for salivary amylase that helps with starch breakdown. While a lower pH in the colon from bacterial fermentation gives favourable changes in disease risk profile.
Then there is your skin which has a pH of about 5. Just what on earth is an alkaline diet trying to achieve by only targeting the blood?!
An alkaline diet ‘works’ because it gives a person a selective list of foods to eat and avoid which means lots of fruits and vegetables (and lemon water too obviously) and less highly processed food, foods high in sugar, and alcohol. That’s it.
You don’t have to believe in the crazy that is the alkaline diet, spend money on alkalinised water, or squeeze a lemon into your water while needlessly cutting out otherwise healthy foods like wholegrains from your diet to make a positive change to your diet and lifestyle.
The downsides
Are there downsides to lemon water? The only ones of note are an effect on your tooth enamel if you’re making this a regular habit along with more stomach acid production. So consider using a straw and rinsing your mouth with plain water afterwards if this could be a concern for you and your teeth. Some people with a history of heartburn can find symptoms are aggravated by drinking lemon water, but this can be variable.
What it all means
Lemon water can be an enjoyable and refreshing drink and an easy way to add a bit of extra vitamin C into your diet. And if you’re drinking lemon water in place of sugary drinks that could be a plus for your body weight and health. But most of the benefits attributed to lemon water are blown way out of proportion.
If you enjoy drinking lemon water, then drink it. Just don’t expect any magical changes in your body weight, skin or body chemistry. At least nothing that can’t be gained from drinking plenty of water throughout the day and eating an orange or two. But if you don’t like drinking it, then you’re not missing out on much at all.
Stacey says
Fantastic blog as always Tim. Very informative.