Salt experiment
Apparently, according to that great bedtime book
The Atlas of Diseases of the Kidney, if I increase my daily sodium consumption from 2 g to 5 g, I will retain an extra litre of water. A litre of water weighs about 2.2 lbs. At the risk of putting on 5 lbs, I decided to consume 10.8 g of sodium in a day, without any food, and see what happened.
Health authorities advise us to drink 2.5 to 3 litres a day of water. Being an obedient sort, I therefore decided to drink 3 litres of tap water with my salt. But I was not going to be stupid. I proposed to drink extra water if I felt thirsty. And to stop the experiment if I felt bad.
Before I began, I ate salt-free food for three days, in order to clear my body of as much sodium as possible.
Day 1
Cool weather.
On waking I weighed 151.5 lb.
(My maintenance zone is 150-158 lb. I deliberately allow 8 lb leeway for unexpected weight rises of several pounds. In practice, I try to keep between 150 and 154. On this day, my weight sat towards the low end of my maintenance zone, which afforded me the luxury of experiment.)
I spent the day mainly working at my desk. Not having to eat meals allowed me to get more done.
Three times during the day, at 9.00, 1.30, and 6.00, I drank one 0.4 litre glass of tap water, followed by another 0.4 litre glass of water into which I stirred a measuring teaspoonful of common table salt. Each very slightly mounded teaspoon of salt weighed 9 grams; therefore it contained 3.6 grams of sodium. I also drank another 0.6 litres of water.
By the end of the day I had consumed:
27 g table salt, containing 10.8 g sodium
3 litres tap water
I used cheap table salt, anti-caking agent and all, because I wanted comparable salt to that in processed foods.
Such is salt’s reputation that I half expected atrocious things to start happening to me. In fact, I felt almost completely normal. I did feel sleepy in the morning, which is unlike me. Apparently sodium can have this effect, and I slept very well that night on it. I never felt thirsty or hungry. I didn't bloat. I hardly peed all day, though I had a normal bowel movement.
In the evening, I took a blood pressure and heart rate reading on my little amateur kit. These kits are said not to be accurate, but they are at least consistent.
My usual readings are all pretty much the same. The previous one was:
Systolic blood pressure: 95
Diastolic blood pressure: 61
Heart rate: 67
The reading I took on the first evening of the experiment was:
Systolic: 106
Diastolic: 66
Heart rate: 60
That my blood-pressure figures had gone up shows, I think, that, even in a healthy person, salt does increase blood pressure. I was surprised to see that my heart rate was down; but when I looked the matter up, I read that heart rate often goes down when blood pressure goes up. Apparently, the heart slows down in response to the increased pressure in the arteries, so as to ease the flow of blood. Good old heart.
Day 2
Cool weather
On waking, I weighed 154.5 lb, a gain of 3 lb.
Even though I knew a gain was on the cards, I was still staggered to see such a brutal gain register in the window of my scale. I had hoped the fact I’d not eaten a single calorie the previous day would offset some or all of any gain in water weight. Perhaps it had done. If I’d eaten normally in addition to taking the three teaspoons of salt, I would surely have put on much more than 3 lb. I felt shaken. There is something truly uncanny about gaining 3 lb after 36 hours eating no food.
I spent the day mainly working at my desk, watching sport, and reading about salt. I pined for my workout more than my meals.
Three times during the day, at 9.15, 2.15, and 6.15, I drank one 0.4 litre glass of tap water, followed by another 0.4 litre glass of water into which I stirred a measuring teaspoonful of common table salt. Each very slightly mounded teaspoon of salt weighed 9 grams; therefore it contained 3.6 grams of sodium. I also drank another 0.6 litres of water. It was déjà vu all over again once more.
By the end of the day I had consumed:
27 g table salt, containing 10.8 g sodium
3 litres of tap water
I was pleased that both days were identical as far as intake, energy expenditure, and weather went.
When I’d woken up that second morning, I found myself breathing quite fast, though not unbearably so. Apparently, this can happen as a result of a slower heart rate, because the lungs try to compensate by taking in more oxygen. For most of the day I felt quite normal, though I had another brief spell of drowsiness, this time in the afternoon. As I mentioned, that was unlike me, but it might simply have been the result of not eating food or drinking tea and coffee.
In the afternoon, I started to pee less tentatively, and by the evening I was peeing normally. In the evening I also contracted a strangely civilised form of diarrhoea, which surprised me because I’d felt no preliminary warnings. These two excretory developments seemed to signal that my body now contained as much salt as it was prepared to put up with.
Forgive me for mentioning the diarrhoea, but it was unlike the normal form. It was as if the tap of a cider barrel was briefly turned to let out a precise measure before being turned off again. The same thing happened again a few hours later, similarly unheralded by intestinal preludes. I looked up the physiology involved, and I believe it was something called osmotic diarrhoea. Apparently, once the body contains as much sodium as it can cope with, it stores the excess in the bowel, from which the sodium draws water out of the rest of the body by osmosis in order to expel it. It’s the same principle as that by which magnesium salts ease constipation; in fact, I read that sodium is also good for constipation, something I never knew. The greater concentration of sodium in the bowel attracts water from the cells and interstices of the body, thus protecting them from over-saturation with salt. The process resembles what is known in trendy circles as a salt flush, though trendy people stop short of using table salt for the purpose. I doubt it sounds it, but this osmotic episode was actually quite pleasant.
By now I felt my body was giving me a message, so I decided to call an end to the experiment. I think it is beautiful the way the body takes over, when the need arises, to maintain health. Mine seems more sensible than me.
My blood pressure and heart rate readings on the second evening were:
Systolic: 114
Diastolic: 68
Heart rate: 52
Once again, my blood pressure had gone up and my heart rate down. This convinces me further that salt does potentially raise blood pressure in healthy people, whatever the salt apologists say. That doesn't mean it will cause health problems, of course; and, to be fair, even these higher readings stayed within the American Heart Association’s “desirable range”. No harm done, I believe.
I was expecting to feel nice and sleepy at bedtime, as I had the night before; but in fact I stayed up till 6 a.m. and then slept for only three hours. To say that is unusual for me is an understatement: I'm rarely up after midnight. I’ve no doubt it had to do with the salt. Maybe we get sleepy as we take in more salt (this has been documented) and less sleepy after that tipping point when excess salt starts being excreted. Perhaps the body wants us to stay awake so that we can pee, or to prevent anything untoward happening to us in our sleep.
I felt very relaxed and spent the night watching classical music videos on YouTube. In fact, I felt almost too relaxed, which I suspect might have been connected to the low heart rate. I’ve never had a heart rate below 60 before. I can usually see my pulse pounding at my wrist, but that night I could not detect it by eye; and when I touched it, it felt sluggish and remote.
*
The following morning I again weighed 154.5 lb.
So on the second day of the experiment I’d neither gained nor lost weight. Given that I’d been peeing freely the night before, I expect I at some point weighed more than 154.5 lb, the difference being afterwards lost in fluid. I’m guessing I might have gone up to 156 or 157 lb, which would have been a gain of 5 or 6 lbs of water weight in two days.
On the second night, round about when I started peeing properly and had the osmotic diarrhoea, I began craving food for the first time in the two days. Very specifically, I craved fruit. That was odd, because I’m not a great fan of fruit, other than dried fruit. And it’s not the sort of thing you expect to crave when you have diarrhoea. But two things strike me about fruit: it contains little sodium, and it is watery.
The day after the experiment ended, I therefore intended a fruit feast, but, cautious of my innards, though they felt fine, I started off with some potatoes to act as a buffer, before setting about eating fruit, fruit and cream, and dried fruit for the rest of the day, to a total of 2444 calories. I also drank and peed with abandon.
*
The morning after that, I weighed 152.5 lb. Despite eating 2444 calories the previous day, somewhat more than my usual intake, I had taken off two of the three pounds I had gained during the fast. I presume most of the loss was water weight.
That night I developed a gouty big toe. I get that about once a year, and I’ve always thought it was caused by rich food. I checked online, and it seems it can also be caused by salt, which crystallises in the tissue. Fortunately, it wasn’t a bad attack. In fact, I'm glad I had it, because it taught me something new about my body.
Conclusions and discussion
The experiment proved satisfyingly neat, because it had so few variables. On the face of it, the result suggests I have a potential water weight of at least 3 lb, probably considerably more since I gained that weight despite a total absence of calorific intake. And sedentary though I was during the experiment, my body must have burned many calories just to tick over. I usually maintain my weight on about 2100 calories a day; which means that during this experiment I sustained a calorie deficit of 4200 calories while gaining 3 lbs.
I believe the experiment gave substance to the two hypotheses that led me to conduct it.
The first was that salt-induced water-weight gain can be so extreme as to make nonsense of the scale. The more dieters learn about water weight and its relation to salt intake, the more they might be able to avoid those high overnight gains that seem so dismayingly random. (I leave aside the question of menstrual weight here, which at least shouldn’t seem so random.)
The second hypothesis was that water is fattening. The fact I remained 1 lb heavier a day after the experiment ended than I’d been before it started supports my suspicion that water weight is insidious. If it were the case that salt-induced water weight consists of no more than a transient influx of water that has no lasting effect on true body weight, then after a post-experiment day of drinking and peeing freely I should have been lighter than I was at the start of the experiment. When I fast, I lose an average of 1 lb a day. By that measure, I would have lost 2 lb over two days of not eating had it not been for the six teaspoons of salt.
*
Any hope that a somehow delayed weight loss was waiting in the wings while I gained and lost my water weight was dashed by this morning’s scale. I am writing this five days after I started the experiment. My weight has now dropped to 151.25 lb, which means, thank goodness, that I’m now a quarter of a pound lighter than I was at the beginning of the experiment. But yesterday I ate only 1801 calories, compared to my usual 2100, because in order to remove the remains of the added weight, I knew that I had to cut calories. And so it befalls us all. Nothing becomes of nothing. I rest my case that salt is fattening.
Of course it might be suggested that I should have gone on eating as normal, been patient, and waited for the day to come when the last pound of the gained weight would drain away of its own accord, as water must, to be followed by the loss of body weight postponed from my fast. Even were that possible, what use is waiting more than five days to a dieter or a careful maintainer? We’ve no alternative but to cut intake to get such weight off: it’s all we know–apart from the fact that weight is weight, whether it’s made of water or not. Fat cells contain a little water; perhaps they like to keep some of the extra they suck in during salt gluts. After all, they prefer to be large: it means they can hold more lipid and glucose. For us weight watchers, who do not prefer to be large, being overweight is about carrying excess water around with us as much as about carrying excess lipid. Maybe we need to be salt watchers too.
*
I’ve looked all over the Internet and not found an experiment like this. Perhaps that’s because I am mad. If nothing else, I believe I have invented the least successful diet plan in the world–one in which you eat absolutely nothing for two days and put on 3 lb in weight.