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  • Writer's pictureTim Rees

Should You Drink Liquid With a Meal?

Does drinking with a meal weaken digestion? I’ve spent the last few weeks pleasantly surprising myself.

POURING WATER INTO A BOWL OF ACID WILL CAUSE A REACTION, RAISE PH AND WEAKEN THE SOLUTION. This is a simple fact. Nutrition science is full of these supposed causes and effects, but the truth is more complex.

Drinking water, or similar, as you’re eating is obviously going to weaken your stomach acid and interfere with the chemical process of digestion, isn’t it? Or, perhaps the stomach isn’t a simple bowl of acid that can be weakened as easily as adding fluid?

For the past two decades, I have deliberately limited the amount of fluid I drank with a meal because I didn’t want to water down critical digestive juices and interfere with my digestion. But, after combing the scientific literature, I began to question this simple idea. Surprised by what I found, I decided to test a new theory; that water doesn’t interfere with digestion.

For the past three weeks, I have been running a one-man experiment (n=1) to discover one thing; should you drink liquid with a meal?

‘In the name of science, I’ve challenged my beliefs by chugging down a whole pint (call it half a litre) with every meal. What I discovered surprised me.’

The battery acid inside us

Healthy human stomach acid has an all-consuming pH of 1.5. As a reminder, a neutral solution has a pH of 7. Inside your car battery, sulphuric acid has a pH of 1. Herbivores range depending on the likelihood of food-borne microbial infections. The anomalous beaver, with a pH of 1.7 pH protects itself from the parasite Giardia. Guanacos, the pretty cousins of llamas, have an alkaline pH of 7.3 in their churning tracts.

Humans have stronger stomach acid than fearsome predators like cats and dogs who digest foods with a 3.6 pH, and 4.5 pH respectively.

Yes, it’s true, you have stronger stomach acid than this fearsome predator. Photo credit.

Amongst the only animals that match or better us—the competition here is the strongest stomach acid—are vultures gleaning nutrients locked inside bones they’ve scavenged from desolate landscapes. And birds of prey that chug down entire rodents along with their piggy-backing ticks.

Today, our strong stomach acid still plays a protective role. We eat fewer half-rotten carcasses but encounter more manure specks on poorly-washed Romaine lettuce. Apart from being the first line of defence, our low pH allows the proper functioning of digestive enzymes, sets the scene for symbiotic gut flora to flourish, and chemically triggers a host of digestive actions. And, having low stomach acid comes with a drove of symptoms.

Parietal cells line our stomachs and secrete hydrochloric acid (HCL) into the space ready to digest just about anything you throw at it. These cells, and others that have equally important roles in digestion, are not inert like the bonded molecules of a bowl.

Unlike a kitchen container that holds only what you put into it, the stomach is a living organ responding to its contents by changing the number of inputs secreted by the many different cells lining it. When you attempt to water down your stomach contents, by drinking during a meal, parietal cells respond by secreting more acid to maintain the low pH.

What does science say?

A quick Google search will start shedding light on what, it seems, is dogma. Studies since the height of the disco era have shown the human body adapts its digestive secretions depending on the types of food present and the amount of fluid.

The human gut is intelligent, containing as many neurons (think brain cells) as can be found in a cat’s brain. The ‘second brain’ effectively makes decisions based on stomach contents and determines what to do about it.

For example, one unfounded fear of drinking water with a meal is that it speeds up a meal’s transit time through the gut, reducing the time our digestive chemicals have to absorb nutrients.

But a study looking at exactly this idea discovered that the solid components of a meal were not rushed through with the liquid. In other words, the gut held onto the solids until they were digested properly. The clever gut gave the liquid portion of the meal a VIP pass to the front of the queue because it doesn’t need to hang about.

This means that within reason, drinking water with a meal has no negative effect because the body seeks homeostasis and control in the digestive tract, just as it does in the blood and everywhere else.

Incidentally, a high pH (weak acid) may also affect one’s glycaemic response—the speed at which the sugars enter the blood—to certain foods by altering the speed of stomach emptying. This response might increase the chances of metabolic dysfunction and diabetes. This is an early call, I admit, and a little off-topic so I’ll dig into it another time. Dr Michael Picco, a consultant gastroenterologist with the Mayo Clinic, echoes the information above by writing on the famous clinic’s website:

‘There’s no concern that water will dilute the digestive juices or interfere with digestion. In fact, drinking water during or after a meal actually aids digestion. Water is essential for good health. Water and other liquids help break down food so that your body can absorb the nutrients. Water also softens stool, which helps prevent constipation.’

It seems that drinking water with a meal may actually enhance digestion. This was contrary to my existing beliefs and so I decided to run my own mini-study.

In the name of science

I don’t know about you but I always seem to get thirsty just as I sit down to eat. But, fearful of watering down my digestive powers I’ve resisted it for the past two decades.

In the name of science, I’ve challenged my beliefs by gulping down a whole pint (call it half a litre) with every meal for the past three weeks. What I discovered surprised me.

I chose a pint because it seems like a lot, too much maybe. My instincts seem to demand about half of that, something like the size of a run-of-the-mill table glass. But I pressed on with more than I wanted in a bid to strengthen the results of my non-randomized, no placebo group, highly flawed, but fun and interesting n=1.

I expected something, I’m not really sure what, but something negative. Maybe some bloating or an uncomfortable post-Christmas dinner type feeling resolved by a nimble twist of finger and thumb about my fly button. I was disappointed.

Well, not disappointed because meal times actually became more satisfying. Drinking water with meals also addressed my life-long ability to completely forget to drink throughout the day. Memories of being an eight-year-old kid came back to me. Running from a painful attempt to pee, I’d ask my Mum for help believing that something grave was afoot.

Nonchalantly, she’d tell me to drink a glass of water. Within seconds the pain would vanish, and my kidneys and attached channels could re-open for business. Aren’t Mums the best?

Go with your gut

The American journalist, H L Menken, said:

‘For every complex problem, there is an answer that is clear, simple, and wrong.’

The simple idea that adding fluids to our stomachs will automatically dilute its content may well be dogma, within reasonable boundaries of course. The stomach is adept at balancing because it monitors and adjusts digestive chemicals dependent on its contents.

If you believed as I did, that drinking water with a meal weakens digestion then perhaps you can try your own, sensible, n=1.

From now on, I will be drinking with meals, except coffee of course

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