Surprising details about salt

water2We recently published a blog abut the health impact of high salt intake. We told you that the body relies on sodium from salt for a variety of functions, including blood pressure and the transmission of nerve impulses. And that it is important that the sodium level in blood is carefully maintained.

But there is more.

The conventional wisdom has long been that if you eat a lot of salt you will become thirsty and drink water, diluting your blood enough to maintain the proper concentration of sodium. Ultimately, you will get rid of the excess salt and water through urine. One way of increasing urine production is to increase blood pressure – the negative health impact of too much salt in the diet.

Sounds simple enough, but some of this may be very wrong.

Surprising findings

Two new studies have put part of this simple theory on its head. In long-term studies of simulated space travel the participants were given a well controlled diet with either 6, 9 or 12 g of salt per day. Eating more salt actually made the participants less thirsty, but somehow hungrier despite the amount of food being exactly the same.

Instead of drinking more, the participants were drinking less when getting more salt. But still increased urine production to get rid of the excess sodium. So where was the excreted fluid coming from? Well, the only explanation available would be that the fluid had been generated from existing body constituents.

How bizarre!

To get to the bottom of the findings the scientists repeated the experiments on mice and found that they burned more calories when they got more salt in the diet. Since they had unlimited access to food – in contrast to the humans above – they ate 25% more just to maintain their weight.

The animals were getting water – but not by drinking it. Instead an increased level of glucocorticoid hormones helped break down fat and muscle in their own bodies. This freed up water for the body to use. However, this process requires energy, thus the mice ate more food.

We already know that a starving body can burn its own fat and muscle for survival. That something similar happens on a salty diet was a surprise. But this is what camels do to create water from the fat in their humps when travelling through deserts with no water.

No, it’s no dieting solution


So could this be a new weight loss fad? To eat more salty foods as salt seems to be involved in weight loss. In contrast to the previous opinion that a high-salt diet encourages a greater intake of fluids, which increases weight.

No, the advice is not to increase salt intake for three reasons:

  • Firstly, more salt in the diet will make you hungrier and you will eat more unless you have a very strong resolve. This would defeat the purpose of the dieting.
  • Secondly, the resulting high glucocorticoid levels are known to cause osteoporosis, muscle loss, diabetes and other metabolic problems.
  • And finally, the increased blood pressure due to the high salt intake can cause heart disease and premature death.

So it is a no brainer to still reduce salt intake. But at least now you know more about what happens when you eat too much salt.

The complexity of weight gain

No fatness gene found.

New fatness gene found.

They have found the culprit, the fatness gene. So all we need now is a bit of gene therapy, or not. Still feel hungry? Well, there is an explanation for that as well. Or is it the carbohydrates that are responsible for the explosion of obesity. According to the latest diet advice you should avoid all kinds of carbs, but eat as much fat as you like. Previously it was the fat to avoid, with a proliferation of low-fat products that now seem redundant. But the Coca-Cola Company and its ilk wouldn’t give up their sugary drinks that easily. They have enlisted a number of fitness experts to promote exercise as the solution. Sounds complex? Well, that is because it is. Let’s look at the ideas one at a time.


We have to start with hunger. Have you ever heard of the AGRP neurons? I guess not, but if you’re often hungry you can blame hunger-sensitive cells in your brain known as AGRP neurons. These neurons are responsible for the unpleasant feelings of hunger making sure that you look for food when your energy level is low, even if you don’t want to. They seem to be an evolutionary part of a motivational system to encourage ancient humans to seek food or water despite having to venture into dangerous environments to do so. Their signals should really be redundant now when food is readily available, but they remain, making it a struggle to maintain a restricted diet and lose weight.

In earlier studies, researchers found that other neurons that promoted eating did so by increasing positive feelings associated with food. In other words hunger makes food taste better, which seems natural. On the contrary the AGRP neurons produce negative feelings. Surprisingly, research results using mice showed that they did not actually have to eat to quiet the AGRP neurons. Instead, the cells ceased activity as soon as an animal saw food or even an artificial signal that predicted food. And their activity remained low while the animal was eating.

If you think that you can just look at food to relieve hunger pangs, think again. Unfortunately, other neurons will make sure that you also eat the food. So no luck there.

Fatness gene

Moving on from the brain to the genome. Scientists have previously found over 100 regions on the human genome that correlate with obesity, likely through regulating the brain’s perception of hunger (here we go again) and the distribution of fat throughout the body. Now scientists at the University of British Columbia have discovered a gene that directly controls the production of fat cells and the growth of those cells, which are precursors to obesity.

The gene can be found in every cell of the body and encodes a protein called 14-3-3zeta. Silencing the gene in mice resulted in a 50 per cent reduction in the amount of unhealthy white fat that is associated with obesity, heart disease and diabetes. And this was despite the mice consuming the same amount of food. The scientists not only identified zeta as the operative protein, but demonstrated a clear cause-and-effect between 14-3-3zeta and fat accumulation.

We get fatter through the multiplication of our fat cells, and through the growth of individual fat cells. And the zeta protein affects both the number of cells and play a role in the growth cycle of these cells. Early days yet, but scientists speculate that there could be possible to suppress the gene or to develop a drug that could block the protein and thus prevent fat accumulation in people who are on their way to become overweight.

But there is a large gap between theory and practice, so no luck yet.

Fat and carbs

Low-fat food popularity (Photo: Barry Ennor).

Low-fat food gained popularity (Photo: Barry Ennor).

So what can you do now? Let’s look at the two individual components of the diet that have been associated with weight gain. A lot of people have very strong opinions about what matters for weight gain, as we have covered before. First it was fat as it seems natural to associate fat consumption with fat accumulation. And fat also provides double the energy per weight compared to the other macro nutrients. Thus industry developed a number of low-fat products to entice consumers. However, they still wanted the products to taste good so in many cases they increased the sugar content and thus energy intake. Such products have been popular for quite some time, but our metabolism is complex so in reality people didn’t really lose weight. Out came the carbohydrate theory, proposing instead that it was carbs that made us fat and not fat in the diet. So fat became free for all but carbohydrate-rich sources like bread, pasta and potatoes should be limited as much as possible. And people on such diets actually lost weight.

So is it proven? Hold on, not so fast. A new study from the US National Institutes of Health presents some of the most precise human data yet on whether cutting carbs or fat has the most benefits for losing body fat. And the researchers show how, contrary to popular claims, restricting dietary fat can lead to greater body fat loss than carb restriction, even though a low-carb diet reduces insulin and increases fat burning.

Despite authoritative claims about carbohydrate versus fat restriction for weight loss, nobody had ever measured in detail what would happen if carbs were selectively cut from the diet while fat remained at a baseline or vice versa. Studying the effects of diet on weight loss is often confounded by the difficulty in measuring what people actually eat. To counter this, 19 consenting adults with obesity were confined to a metabolic ward for a pair of 2-week periods, over the course of which every bit of food eaten was closely monitored and controlled. During the first period, 30 per cent of baseline calories were cut through carb restriction alone, while fat intake remained the same. During the second period the conditions were reversed.

At the end of the experiment body fat lost with dietary fat restriction was greater compared with carbohydrate restriction, even though more fat was burned with the low-carb diet. However, over prolonged periods the model predicted that the body acts to minimize body fat differences between diets that are equal in calories but varying widely in their ratio of carbohydrate to fat. So the conclusion is that although not all calories are created equal when it comes to body fat loss, over the long term, it’s pretty close.

So feel free to limit energy intake the way you feel most comfortable with, as long as it is consistent over time.


Exercise not enough to reduce weight (Photo: Sangudo).

Exercise not enough to reduce weight (Photo: Sangudo).

The remaining part of the energy equation is energy expenditure. Coca-Cola, the world’s largest producer of sugary beverages, is backing a new “science-based” solution to the obesity crisis: Exercise more and worry less about cutting calories to maintain a healthy weight.

The beverage giant provides support to a new nonprofit organization called the Global Energy Balance Network with a team of influential scientists who are promoting the message in medical journals, at conferences and through social media. And the message:  Weight-conscious consumers are overly fixated on how much they eat and drink while not paying enough attention to exercise.

This message has not been uncontested with health experts saying it is misleading and an effort to deflect criticism about the role sugary drinks have played in the spread of obesity and Type 2 diabetes. It is clear that exercise has only minimal impact on weight compared with what people consume. A food industry critic, professor Marion Nestle, is especially blunt in her comments: The Global Energy Balance Network is nothing but a front group for Coca-Cola. Coca-Cola’s agenda here is very clear. Get these researchers to confuse the science and deflect attention from dietary intake.

While people can lose weight in several ways, many studies suggest that those who keep it off for good consume fewer calories. Growing evidence also suggests that maintaining weight loss is easier when people limit their intake of high glycemic foods such as sugary drinks and other refined carbohydrates, which sharply raise blood sugar.

So what to do?

There is nothing much you can do yet about the genes you have inherited from your parents. But you can make sure that you eat a nutrient dense diet rather that an energy dense diet, and reduce overall energy intake in a way you feel comfortable with. As scientists say about their studies, rubbish in, rubbish out, or in this case junk food in, belt out. Physical activity is important and certainly helps. But studies show that exercise increases appetite, causing people to consume more calories. Exercise also expends far fewer calories than most people think. And to compensate the fluid loss with an energy drink at the end of the exercise completely defeats the purpose.

Related articles

Fit with a grapefruit, or not?

Hope to lose weight with grapefruits (Photo: fantasyhealthball)

Hope to lose weight with grapefruits (Photo: fantasyhealthball)

It has long been the belief among some dieters that regularly eating grapefruit can help shed weight. Eat half a grapefruit before each meal and lose 10 pounds in 10 days was the simple mantra. The Grapefruit Diet has actually been along for some 80 years by now. Historically, supporters have claimed that grapefruit contained a fat-burning enzyme or some like compound. For a while it was even called the Hollywood Diet and as we all know many Hollywood stars keep slim forever so it must work. Or not?

There has been much ridicule of such a crazy diet. It has even been satirised in a song with the usual irreverence and mild cruelty of singer “Weird Al” Yankovic. But fad diets will never die — not as long as we live in a world where people seek immediate gratification by following promises to rapidly drop off weight. Or not?

The appeal of instant results perpetuates a growing demand for products or plans assuring overnight success. With more and more people across the globe becoming overweight or obese, fad diets have multiplied. Although fad diets are typically synonymous with dubious science, desperate times require desperate action. Or not?

Unfortunately, quick weight loss is almost always followed by quick regain of weight. That seems to be the inevitable rule. But if we forget the outrageous claims of the proponents of the Grapefruit Diet, might it be some truth behind the claims?

New surprise findings

Well, surprise, surprise, new research from UC Berkeley’s Nutritional Sciences and Toxicology department suggests that the grapefruit diet might actually work, at least to some extent. Previous studies on the potential benefits of the grapefruit diet have been small, not well-controlled, and contradictory.  The new study found that mice fed a high-fat diet gained 18% less weight when they drank grapefruit juice compared with a control group of mice that drank water. Juice-drinking mice also showed up to a 17% decrease in blood glucose levels, and a threefold decrease in insulin levels.

Unbelievable, so to confirm their findings, the researchers repeated the study several times. Each time they randomly divided the mice into six groups, including a control group that drank only water. For the others, clarified, pulp-free grapefruit juice was diluted with water at different concentrations, and sweetened with saccharin to offset grapefruit’s bitterness. Glucose and artificial sweeteners were added to the control group’s water so that it would match the calorie and saccharin content of the grapefruit juice. Half of the groups were fed a high-fat diet and half a low-fat diet. Results confirmed that the mice that ate the high-fat diet and drank diluted grapefruit juice gained less weight than their control counterparts.

Lingering doubts

Still lingering doubts about the power of grapefruits (Photo: Wikimedia)

Still lingering doubts about the power of grapefruits (Photo: Wikimedia)

Now it starts to be a bit confusing. It has previously been proposed that a compound in grapefruit juice called naringin could be the key agent responsible for weight loss. So the researchers replaced the grapefruit juice with this compound. And it had no effect on weight loss but at least reduced blood glucose levels. There is thus a lack of a molecular explanation to their initial findings. Although not a requirement, to be trustworthy it is always good to know why you get certain surprising results.

You should also know that the study was funded by the California Grapefruit Growers Cooperative. Of course the researchers claim that this had no influence on the outcome of the studies. Although I am sure that the researchers acted independently, there are indications that the outcome of externally funded studies often come up with findings pleasing to the funding body. Maybe not in this case, but there is a lingering doubt.

And finally mice and humans that are quite different in their food choice and metabolism might not react the same way to grapefruit juice. Or we may!

Go for it

So what are those caveats to a believer. Go for it if you like as long as you’re careful if on certain medications. There are clear warnings that grapefruit can increase the absorption of some drugs into the bloodstream, creating a potentially dangerous interaction.

Related articles

Slimming during your sleep

Losing weight during sleep (Photo: RelaxingMusic)

Losing weight during sleep (Photo: RelaxingMusic)

When you go to bed and close your eyes you might start a process of losing weight. It is really contrary to what you would believe. The normal theory is if energy in through food exceeds energy out through exercise you will gain weight. And during sleep you don’t get much exercise unless you are sleep-walking. But read on and you will learn what a little cold and the very small pineal gland can do to your body.

The pineal gland, or the “third eye” as it has sometimes been called, is a small endocrine gland situated in the  brain. Its shape resembles a tiny pine cone, hence its usual name. It seems to have acted as a light sensitive eye in some ancient animals and still does in a few surviving species like the lamprey, thus the naming as the third eye. As a matter of fact light still regulates its activity. Light signals are sent from photosensitive cells in our eyes and through a brain pathway to the pineal gland that in turn regulates our circadian rhythm that is so vital to proper sleep. It does this by producing melatonin during the night since the production of melatonin is stimulated by darkness but inhibited by light.

The illusive brown fat

Now we have to look at brown fat to complete the story. Brown fat is one of two types of fat found in mammals. The other type is the normal white fat that we only use for energy storage. However, the primary function of brown fat is not to store energy but to generate body heat. This is vital to newborn babies that cannot shiver and it makes up about 5% of their body mass. It is located on the back, along the upper half of the spine and toward the shoulders. Brown fat cells are actually more related to muscle cells than to white fat cells in that they carry a much higher number of iron-containing mitochondria, the energy machines of our cells, and more capillaries to supply their greater oxygen needs. Both factors that create the brown colour.

The brown fat will decrease with age and was initially believed to be almost non existent in adults. However, new imaging technologies have found small amounts in the neck, upper back, and clavicles of adults.  Aside from knowledge of its anatomic presence, little was known about the role of brown fat in adults until the past few years. Now, new research has shown that it also can contribute to regulating body temperature in adults in that this highly metabolically active tissue will burn energy to generate heat when we are exposed to cold temperatures. Dutch researchers subjected a group of people to a 15-16 ºC temperature for 6 hours per day and found that the brown fat increased its metabolic activity and became more efficient in keeping us warm. Similarly, Japanese researchers exposed healthy human subjects to cold and found an increase in brown fat activity and energy expenditure, and a decrease in body fat mass at the end of the study. The authors of both the Dutch and Japanese studies concluded that regular exposure to colder temperatures could be effective in reducing the prevalence of obesity in the population.

Melatonin an alternative to cold

Being cold is not everyones cup of tea (Photo: ObertoMaidelys)

Being cold is not everyones cup of tea (Photo: ObertoMaidelys)

Now we might not like to spend time in cold temperatures to lose body weight, but, you guessed it, the pineal gland comes to the rescue. Apart from regulating the circadian rhythm, melatonin is also involved in energy metabolism and body weight control. Melatonin promotes the recruitment of brown fat cells and enhances their activity, thus raising the body’s basal metabolic rate. And there is more. Spanish scientists have an explanation to the puzzling conundrum of the effect melatonin has in countering obesity. They found that melatonin can transform white fat to beige fat, a structure with similar effects to brown fat. While white fat stores calories leading to weight gain, beige fat helps regulate body weight by burning calories.

So a good night’s sleep might stimulate your melatonin production and help you lose weight. If you’re a light sleeper you might be happy to know that melatonin can also be found in fruit and vegetables like mustard, Goji berries, almonds, sunflower seeds, cardamom, fennel, coriander and cherries. Sleeping in the dark and consuming the right fruit and vegetables could help control weight gain and prevent cardiovascular diseases associated with obesity. And why not the occasional stay in a cold environment. There are melatonin pills available as well for the lazy. And just before you go overboard with your sleep patterns, you should know that some of the data come from animal experiments and will still need to be confirmed in humans. But why destroy a good story?

Related articles