Having studied naturopathic nutrition a few years ago, I became aware of just how much my diet affected my moods and my energy levels. What I also learned is that what you eat can affect all sorts of bodily functions, including how much you sweat. We are all unique, and hence we all react differently to foods. If you are not at your peak, it's always worth having a look at your diet. To start to understand our individual reactions to food and drink, we need to cover two basics - digestion and homeostasis in the body.
Digestion - How could eating affect body heat?
Why does eating certain foods make you hotter and more prone to sweat? Have you ever noticed that you feel warmer after a meal?
After we eat food, substances in the digestive system called enzymes break proteins down into amino acids, fats into fatty acids, and carbohydrates into simple sugars (for example, glucose). None of this comes for free, and the body has to work to break food down. Just like when your body is working for physical exercise, the work of digestion causes the body to produce heat. Too much heat and you start to sweat.
Homeostasis in the body
Homeostasis means balance or equilibrium. It is the ability to maintain internal stability in an organism to compensate for environmental changes.
One of the most important examples of homeostasis is the regulation of body temperature. Humans hold their body temperature at about 37°C (98.6°F). When your hypothalamus (internal thermostat) senses that you're too hot, it sends signals to your sweat glands to make you sweat and cool you off. When the hypothalamus senses that you're too cold, it sends signals to your muscles that make your shiver and create warmth. This is called maintaining homoeostasis. You'll see why that is important in the next section.
Food and drink which is thought to increase sweating - fact and fiction
Some foods are thought to increase sweating, others are considered to have the opposite effect. If you do have a problem with excessive sweating or odour, some of these simple dietary tips may help. But watch out, this topic is full of myth. I've done my best to show where the research helps us separate fact from fiction.
1. Hot Spicy Foods
According to Barry Green of John B. Pierce Laboratory in New Haven "spicy foods excite the receptors in the skin that normally respond to heat. Those receptors are pain fibres, technically known as polymodal nociceptors. They respond to temperature extremes and to intense mechanical stimulation, such as pinching and cutting; they also respond to certain chemical influences. The central nervous system can be confused or fooled when these pain fibres are stimulated by a chemical, like that in chilli peppers, which triggers an ambiguous neural response."
Put simply, spicy foods like capsaicin (hot chilli) stimulate nerve receptors in your skin and "trick" your nervous system into thinking you're hot. This is so convincing to your internal thermostat (the hypothalamus) it sends out a signal to activate your sweat glands to cool you down. Just have a look around the room next time you go out to an Indian restaurant!
So, if you don't want to sweat, it is a good idea to avoid foods containing too much hot chilli.
There is a lot written about coffee and how it affects us. There are articles either promoting the use of coffee for sports and also warning you about its dehydrating effects. There is some research published by NCBI, which indicates that coffee does increase body temperature and sweating (in athletes). This, combined with my experience of coffee sweats, makes me think twice about when I drink the stuff.
Coffee is believed to have two reasons for making you sweat. Firstly the caffeine in coffee stimulates your central nervous system, which activates your sweat glands. Secondly, it's a hot drink, and the extra heat could make you sweat (which is the case for any hot drink).
There has been some research which shows that hot drinks both help to keep you cool and can make you sweat more in warm climates. Dr Ollie Jay found that after subjects drank a hot drink, they produced more sweat. This increase in sweat (and sweat evaporation) led to an overall decrease in body temperature. Here's a good article on how hot drinks can keep you cool in summer.
Alcohol dilates the blood vessels in your skin. The rush of warm blood makes your skin hot, and this, in turn, triggers you to sweat. The same thing happens during physical exercise when blood vessels dilate to rid the body core of excess heat. Only in this case, there is no excess heat - just the alcohol having the same effect.
There is a lot written about alcohol and how it affects sweating. If you want more detail, try this summary in MD Health.
4. Large amounts of meat - Meat sweats
Though they're said to occur, scientific evidence does not show that 'meat sweats' are a real thing. This said many people experience 'meat sweats' and they can be observed during competitive eating.
One possible explanation is the 'thermic effect' of protein. We have to work harder to digest protein than we do to digest carbohydrate. It is hypothesised that in competitive eating, the combination of increasing amounts of adrenaline and protein cause the body to increase in temperature and subsequently cause an eater to sweat, a lot!
So, whilst there isn't any scientific evidence for this one, you may want to hold back on large amounts of meat when trying to impress.
5. Salt (NaCl)
The amount of sodium an individual requires depends entirely on genetics, current health and level of physical activity. Unlike pure sodium, salt is made up of a combination of both sodium and chloride (NaCl).
Some say that when you overeat salt, your body tries to get rid of the excess by sweating. But the evidence seems to counter this. The current medical view is that too much sodium may result in increased water retention. This is a leading cause of high blood pressure, kidney failure and hypernatremia. The kidneys function is to filter out toxins and excess sodium from the body. If there is more sodium than the kidneys can deal with, the sodium will accumulate in the blood, and kidney failure may ensue. You have been warned!
How much you sweat is based primarily on genetics, body temperature and physical activity. Although sodium levels and amount of sweat are entirely unrelated, it's good to keep an eye on sodium levels.
According to the NHS in the UK, the average adult eats about 8.1g of salt (3.2g sodium) on average a day. It is recommended that adults should not be eating more than 6g of salt (2.4g sodium) a day.
The American Heart Association recommends no more than 2.3g sodium a day and an ideal limit of no more than 1.5g per day for most adults.
6. Processed Foods, which are often fatty
While there are claims that processed foods can increase sweat, I've not (yet) found any scientific studies on the matter. Processed foods tend to be high in fat which, like protein, makes your body work to digest. More work equals more heat which increases the possibility of sweating. They also tend to be high in salt. So while the evidence is unclear, it might be an idea to avoid processed food if only for the benefit of your waistline and general health.
Adults are about 50 to 75% water. We need to stay hydrated, and a lot has been written about this.
Water can absorb and transfer heat well, so the human body uses it to regulate temperature (maintain homeostasis). Too much, or too little, can cause problems for us. The average adult needs 1.5 to 2 litres a day. Paying attention to water intake could make a difference to your bodies homeostasis. Hence, if you are having any problems, it's worth monitoring your water intake.
Keep it Natural
Of course, sweating is a natural human reaction to help our bodies stay cool. If you do sweat more than you want, then taking a look at what you eat may be helpful. In the meantime, to help prevent sweat showing on your outer layers, I would (of course) recommend you try a Robert Owen undershirt.