This blog is about the intersection between evolutionary biology and food. But also about practical applications, sustainable agriculture, and general tasty things.
Fasting, particularly the type known as intermittent fasting, has been popular in many health communities for awhile. Many people learn about it through Mark Sisson, Leangains, or Eat Stop Eat. Some people do it for weight loss, other people do it for its other potential benefits such as boosting cellular cleanup known as autophagy.
But it has been getting some negative press. The latest I saw was this horror story: How Intermittent Fasting Saved Me…while Slowly Killing Me:
By week 8, my chin was breaking out more. By week 9, more, by week 10, I had legitimate acne; large cist-like monsters just hanging out under my skin. A bumpy, unhealthy face, tired eyes, no energy, what my mom called a “depressed” state of mind. My hormones were ALL out of whack.
Yikes! But many people report that fasting has great benefits. That was my own experience. At first at least. I liked the idea of IF because I've always hated breakfast and it jived with my natural tendency to want to work without thinking about food. And often it was pretty awesome for me. I felt energetic and focused.
But sometimes I just felt terrible. Fatigued, lacking focus, light-headed, distracted by gnawing hunger. Was it time to ditch the IF habit?
No, because this was only happening sometimes. Clearly there were times my body was not up for fasting. And others when it provided a boost.
So over time I've figured out a few rules that keep me from fasting when it's going to back-fire. Of course this requires you not follow a strict regimen, that you be willing to skip fasting when it's not the right time. Don't worry you can always go back to Leangains or whatever later. And you'll be better prepared to do it if your body isn't a mess. Because fasting in the wrong context can stress your body, telling your biological systems that you are in a very bad place. And when that happens, it can respond dysfunctionally.
A borderline case is when you feel like you are getting sick. Often I will fast in this case and end up not getting sick. But the research on this matter is mixed, with few studies in humans. One study showed that it might be a good idea to feed a cold and starve a fever. Instead of fasting, it might be a good idea to stick with gentle easy to digest immune nourishing foods like soup or stews. There is even some scientific evidence that chicken soup might help fight colds
edit: and as someone pointed out in the comments on Facebook, it's probably not the greatest idea to fast when you are pregnant or nursing. I'd hope that would be obvious...but you never know. And it seems to be a problem in some cultures.
I'll fully admit that sometimes this is hard to follow. When I'm stressed and have a big project due, the last thing I want to think about is breakfast. But to be honest, I've found it's better to eat something "bad" in this kind of situation than to fast. I wish I could just skip a meal if there are no good choices, but sometimes I have to bite the bullet and know that while what I'm eating isn't optimal, at least I am not pushing my body into a bad place.
And as always: if something makes you feel bad and isn't working for you, it's probably a good idea to stop doing it.
Regardless of the uniquely nourishing properties of meat, there are people who just don't want to eat meat. There are also people who might want to abstain from it periodically. Sometimes in the blogosphere it might seem as if it's a choice between steak and absurdly dysfunctional raw vegan diets. This is a false dichotomy perpetuated by people who have a bizarre distorted views about animals.
Enter animals that definitely don't have feelings or interests beyond very basic biological urges. In his excellent essay on the idea of oysters being OK for people who otherwise would be vegan, Christopher Cox says:
But what if we could find an animal that thrived in a factory-farm cage, one that subsisted on nutrients plucked from the air and that was insensate to the slaughterhouse blade? Even if that animal looked like a bunny rabbit crossed with a puppy, it would be A-OK to hack it into pieces for your dinner plate. Luckily for those of us who still haven't gotten over the death of Bambi's mother, the creature I'm thinking of is decidedly less cuddly. Biologically, oysters are not in the plant kingdom, but when it comes to ethical eating, they are almost indistinguishable from plants. Oyster farms account for 95 percent of all oyster consumption and have a minimal negative impact on their ecosystems; there are even nonprofit projects devoted to cultivating oysters as a way to improve water quality. Since so many oysters are farmed, there's little danger of overfishing. No forests are cleared for oysters, no fertilizer is needed, and no grain goes to waste to feed them—they have a diet of plankton, which is about as close to the bottom of the food chain as you can get. Oyster cultivation also avoids many of the negative side effects of plant agriculture: There are no bees needed to pollinate oysters, no pesticides required to kill off other insects, and for the most part, oyster farms operate without the collateral damage of accidentally killing other animals during harvesting. (Relatedly, although it's possible to collect wild oysters sustainably, the same cannot be said for other bivalves like clams and mussels. These are often dredged from the seabed, disrupting an entire ecosystem. For that reason, it's best to avoid them.)
If you are slightly less sensitive as least less than David Foster Wallace (as I am), you might want to also consider the lobster, as lobster harvesting has also become much more sustainable. Other shellfish options are a bit more murky. Good shrimp is exceedingly hard to find, most of it raised in polluted cesspools in Asia or caught from a now-destroyed Gulf. Clams are often harvested through dredging, which destroys the sea floor. Overall, while I do have some access to things like local diver scallops, I have found that even though I live on an island, meat is much easier to source.
The role of shellfish in human evolution is controversial, but they are very easily gathered and treasured by many cultures. In Human Brain Evolution: The Influence of Freshwater and Marine Food Resources there is a wonderful table, which is "amount of each major food groups required to meet the daily requirement for five brain-selective minerals- iodine, iron, zinc, copper, and selenium." You only need 900 g shellfish vs. 5000 grams meat vs. 9300 grams fruit vs. 47,000 grams cow's milk. The book notes that in evolution "a combination of shellfish, fish, nuts, eggs, meat, and fruit seems to be more likely than exclusive consumption of one food group..." Either way, you don't need much shellfish in your diet to make a difference between a mediocre vegetarian/vegan diet and an excellent omnivorous one. Besides those minerals so important in brain development, shellfish also provide DHA, B12, and taurine, also very important for the brain.
I have occasionally relied primarily on a shellfish-based diet and the major limit to this is shellfish don't have much in the way of calories. Eat just oysters for dinner and you will be hungry. You also need to rely on a variety of other nourishing calorie sources like coconut, roots, and fruit. An excellent staple is shellfish boiled in coconut milk with some roots. Mmm.
Does the Mediterranean Diet Even Exist? asks the NYtimes
The Mediterranean diet was always a composite. Spaniards love pork; Egyptians, as a rule, do not. In some regions, people made pesto with lard, not olive oil. “There is no such thing called the Mediterranean diet; there are Mediterranean diets,” says Rami Zurayk, an agriculture professor at the American University in Beirut. “They share some commonalities — there is a lot of fruits and vegetables, there is a lot of fresh produce in them, they are eaten in small dishes, there is less meat in them. These are common characteristics, but there are many different Mediterranean diets.”
The healthy versions of these diets do have one other thing in common: they are what the Italians called “cucina povera,” the “food of the poor.” In Ancel Keys’s day, Mediterraneans ate lentils instead of meat because they had no choice. “A lot of it is to do with poverty, not geography,” says Sami Zubaida, a leading scholar on food and culture.
Well, I agree that most low-meat diets around the world have more to do with poverty rather than health, that's not why some Greeks may have been eating lentils. The Greek Orthodox form of Christianity prescribes fasting for a little over half the year. Fasting involves eating not only less, but forgoing all animal products besides invertebrates like shellfish and insects (not many people take advantage of this). This letter to the editor from the journal of Public Health Nutrition asks why Ancel Keys didn't note that in his study.
When laymen break these fasts they don't eat lentils, that's for sure. It's a time to enjoy meat, dairy, and fish.
Yesterday I was reminded of this shrimp dish I ate in Stockholm when I was reading Anne's Blog, an excellent Swedish food blog. I don't know why, but I encountered such shrimp + lime + colorful vegetables/fruits recipes in Sweden. This dish had mango, chili, scallions, and lime. Last night I made a variation of it with chili-garlic paste, ginger juice, mango, kiwi, lime, shredded dried coconut, a little dash of coconut aminos and some wild shrimp. Unfortunately, wild shrimp is quite expensive here and not exactly local. I might try this with local scallops next time, though my secret dream is to buy a giant warehouse and raise freshwater prawns in NYC.
My new favorite ingredient is ginger juice. I always used to buy ginger and not be able to use all of it before it shriveled up. But ginger juice is a great way to get all that flavor without much work. I'm also a big fan of chili garlic paste, which is called Sambal Oelek at the local Indonesian markets. I know it's cheaper to just buy ginger and chilies and chop them myself, but I've been so swamped with work lately that these ingredients are a must.
I keep seeing things about how fasting isn't paleo because the paleolithic was an environment of abundance. So? So is Brooklyn, that doesn't mean we eat all the time.
Ever just not feel like cooking? Ever plan your day badly and end up skipping breakfast? I wouldn't be surprised if hunter-gatherers did the same. After all, butchering animals IS tough work.
So I'll just reference one of my old posts on Daniel Everett's book Don't Sleep There Are Snakes, which is about the Pirahã tribe: "They have no food preservation methods and simply eat when they have made a kill. Apparently being hungry is no obstacle to exerting themselves: "I have seen people dance for three days with only brief breaks, not hunting, not fishing, or gathering -- and without stockpiled foods."
So fast if you want to, but the idea that fasting is inhuman and damages your metabolism seems bunk to me. Lean Gains has a good post about it. That said, I think fasting is for HEALTHY people. If you are trying to repair your body, eat well and then fast when things are normalized a little better. I also think that fasting should never feel bad. If you are healthy and fasting properly you should be perfectly functional, not obsessed with food, and in a good mood. If you aren't those things...maybe you need to take a step back and nourish yourself first.