Sunburn and UV
SPF 30
We’re constantly reminded how harmful the sun and sunburn are. I used to buy sunscreen with at least SPF 30 and apply it generously and often — even though I always found the greasy residue revolting. Not to mention the marks on clothes and the need to wash your hands afterwards if you didn’t want to be reminded of the sliminess all day.
But sunscreen was necessary: I burned quickly. Itchy, peeling skin drives me mad, and I can do without the painful shower (typically the first sign I’ve overdone it). The pain, that is — not the shower.
Since I never really developed a lasting tan, I was also indifferent to the fact that sunscreen largely prevents tanning. It never stuck for long anyway.
SPF 1
After some time on a Metabolic state in which the body burns fat rather than glucose for fuel. Characterised by a measurable level of ketone bodies in the blood. → more diet (I can’t remember exactly how long), I started coming across reports from various people who had stopped getting sunburned.
At some point I decided to try it myself.
It worked: I no longer burn. I haven’t bought or used sunscreen in at least 10 years.
If I overdo it my skin does go red, but the painful shower is gone, the skin doesn’t peel and doesn’t itch. Instead the redness fades within a day or two and my normal skin tone returns.
srsly?
An explanation I’ve come across that fits my diet: avoid Fatty acids with multiple double bonds in the molecule — chemically more reactive than saturated fatty acids. Typically (but not exclusively) plant oils. Omega-3 and omega-6 fall into this category. → more What is commonly called 'fat' consists chemically of a glycerol molecule with three fatty acids. That's a level of detail we'll rarely need here. → more, and eat Fatty acids with no reactive molecular component — normally solid at room temperature. Typically animal fats. → more fats instead. This gives the body the opportunity to incorporate those saturated fats into cell walls. Saturated fats are less reactive, and therefore more stable under UV exposure, whereas unsaturated fats are significantly more reactive at their double bonds and can be damaged by UV radiation.
So when polyunsaturated fats are incorporated into cell membranes, they react much more strongly to UV exposure. And, if I understand it correctly, that reaction is what constitutes “sunburn”.
In my diet I’ve largely avoided polyunsaturated fats (in the form of seed oils). Olive oil occasionally, but mainly saturated fats: coconut oil, butter, animal fat. And since my initial goal was purely ketosis, I didn’t hold back on fat.
As far as sunburn response and skin ageing go, this strategy seems to work very well — and that’s the part I can validate anecdotally and personally.
Does anyone have a different explanation?
