Nature Boy looked doubtfully at the meal.
鈥淚 think my junk-food-eating gut bacteria are going to riot if I keep eating all these 颅salads, steamed vegetables and grains. It鈥檚 been more than almost six months since they鈥檝e had a good feed.鈥�
鈥淵ou鈥檒l be fine,鈥� I said, passing him a bowl of chopped kale, walnuts and apple.
鈥淚 don鈥檛 know,鈥� he said. 鈥淧eople revolt with their bellies, and my gut colonies of 颅Pizzabacilli and Doritosphilia are a big part of my belly.鈥�
We both paused and looked down at his belly.
鈥淟ooks like there鈥檙e less there than there used to be,鈥� I say.
鈥淭hat鈥檚 the problem. All these greens-, bean- and fibre-friendly microbes that you鈥檙e cultivating with this food are gentrifying my intestinal real estate. The original occupants aren鈥檛 happy about it and they鈥檙e getting restless 鈥� Don鈥檛 look at me like that, I鈥檓 just warning you. It could get messy if I don鈥檛 throw them a crust soon 鈥� 颅preferably one stuffed with high-fat, rubbery cheese and laden with pepperoni.鈥�
We 鈥� that is, I鈥� have been on a whole-foods kick lately. Tired of feeling tired and sick of zombie-like mid-afternoon slumps (Must. Sleep. Now.), I鈥檝e overhauled my鈥� ahem, our 鈥� eating habits.
Most of the food in the house these days doesn鈥檛 come sealed in foil or plastic sacks or boxes. And, to date, no one has managed to grow carrots or heads of lettuce with built-in nutrition facts tables to show how many grams of carbohydrates, fats, salt, 颅calcium, vitamins, etc., a serving contains.
But, as Nature Boy pointed out, it鈥檚 not just what you eat, it鈥檚 what you feed.
Thanks to the wonders of gene 颅sequencing, we now know that as many as 100 trillion individual microbes live in the human gut. These include fungi, viruses, microbes known as archaea 鈥� which 颅scientists once thought were bacteria but are actually 颅something different 鈥� as well as some 15,000 species of bacteria.
Researchers estimate that all of the microbes in one typical adult human 颅intestine weigh about as much as the same adult鈥檚 brain 鈥� about 1.25 kilograms.
Most of these microbes hang out in our lower intestines, where they do vital work to keep us, their hosts, healthy and happy.
They break down plant fibre in the food we eat and help us absorb vitamins, 颅minerals and other nutrients from our food. Some manufacture crucial-to-us vitamins as waste products.
They neutralize harmful chemical 颅by-products of the digestive process. They regulate gut-oxygen and gut-acidity 颅levels. They police each other. They control 颅inflammation and other immune responses. They protect against disease. They may even help regulate hormones such as insulin and stress hormones.
Those are the good guys. Others 鈥� 颅including those that thrive on high quantities of super-processed sugar and pizza 鈥� are less desirable, but we can tolerate them in low numbers 鈥� kept low by the entire gut community.
Gut bugs feed on what we feed them. However, they鈥檙e particular about who dines on what. Each species brings its own special skills and dietary needs to the intestinal颅 颅buffet.
Some specialize in breaking down fibre found in citrus fruits. Some are skilled at snacking on the cellulose that makes 颅celery, lettuce and peppers crunchy. Some 颅prefer the pectin found in apples, plums and pears. Bean-eating bacteria bust apart the long 颅carbohydrates in kidney beans and 颅black-eyed peas, releasing gases that then need to be vented.
Some stick to snacking on sugar. If there鈥檚 a food, there鈥檚 a gut microbe with the tools to deal with it.
Feed it what it needs, and a microbial species thrives. Starve it and it fails, and neighbouring species that can feed on what鈥檚 available take over.
Researchers who spend way too much time with poo have found that species-颅population levels within a person鈥檚 gut 颅community can change within hours after he or she has eaten.
So, when Nature Boy complains that his pizza-phillic and Doritos-specialist gut critters are complaining about not getting enough of their particular food groups, he has a point.
Not that it鈥檚 a good point.
But it is a point.
鈥淲ell, then, if they can鈥檛 get bread and rubbery cheese and orange food dye,鈥� I told him, pointing to a plate of tofu, 鈥渓et them eat bean cake.鈥�
鈥淣ow you鈥檙e just asking for trouble 鈥� explosive trouble,鈥� he said.
