The 5 Stages of Digestion

Losing Sleep Can Wreck Your Gut_It changes your gut microbiome

Today’s guest post is from Wade T. Lightheart and Matt Gallant at biOptimizers, who have been on Bulletproof Radio twice — in episode 515 and episode 611 — to discuss little-known truths about gut health, probiotics, the microbiome, enzymes and more. 

In this post, they explain how your food is broken down, also sharing how to optimize or biohack each phase so that you can maximize your digestion. 


Woman eating chocolate for gut health

Have you biohacked your digestion? Now is the time.

When Hippocrates, the father of modern medicine said: “all disease begins in the gut,” he was referring to digestion. 

There are countless ways to enhance your gut microbiome health: you can buy probiotics, experiment with fermenting foods, or eat loads of vegetables high in resistant starch. But if you don’t digest your food properly, you won’t get far. The most powerful path to gut health, and whole-body health, will always involve fixing your digestion. 

To digest your food thoroughly, it’s critical you understand the 5 distinct stages and the essentials of each stage. 

Stage 1: Preparation

teen cooking skills_headerThis first essential stage involves smelling, tasting, touching, and chewing your food, with the goal of getting it ready to be further processed by the rest of the digestive process. Unfortunately, most people are moving too fast, multitasking too frequently, and are under too much stress to connect with their food and chew properly. 

But chewing is absolutely essential, because it determines which enzymes are activated in your saliva, including amylase, protease and lipase. Amylase, secreted from the parotid glands on the sides of your mouth below your ears, helps with carbs. The submandibular glands, located under your jawbone, secrete protease to help with protein breakdown.  Lastly, sublingual glands, which means “under the tongue,” help produce lipase, which aids in fat digestion. 

Again, it’s critical to connect with your food like our ancestors did and avoid eating while distracted or rushing. In a study, published in the Gastroenterology journal, researchers found that metabolism and digestion are meaningfully altered under perceived distraction and stimuli. 

Stage 2: Secretion

As you chew your food and mix it with saliva and enzymes, the process of breakdown begins. The initial mixture of food then moves through your esophagus, which is a tube-like organ that links your mouth to your stomach. 

Interesting fact: the process of peristalsis – the tightening and relaxation of muscles in the intestine to transport food and waste products – causes food to move in a single direction, downward only. This means that even if you ate upside down, food would ONLY continue to move through your esophagus to your stomach. 

Take our word for it – don’t try it. It’s easy to choke when you’re eating upside-down. 

As food enters your stomach through a muscular ring, which opens and closes in order to keep acid from coming up into your esophagus, gastric acid (HCL or hydrochloric acid) and enzymes secretion both activate. This process is especially crucial for humans, as we are the only animal that cooks its food. Cooking removes a lot of the enzymes present that would normally assist with digestion. 

It’s also why enzyme supplementation is so critical, as we discussed with Dave in Bulletproof Radio episode 611. As we age, our enzyme levels decline and digestion begins to slow down. We know that enzyme supplementation works: in fact, a double-blind, crossover study confirms the efficacy of digestive enzyme supplements in optimizing digestion.

Stage 3: Breakdown

Both enzymes and hydrochloric acid both play critical roles in the next phase of digestion, which is about breaking food down from its base form, into usable building blocks and nutrients. When your digestion works well, protein converts into amino acids. Complex carbohydrates break down into glucose (sugar) molecules. Grams of fat must become free fatty acids. 

Take protein digestion, for example. Proteins are made up of amino acids, which your body can use. So, it’s your digestive system’s job to break down protein that you eat into amino acids. When you eat protein, your stomach acid activates a substance called pepsinogen that will turn into the enzyme pepsin. Pepsin digests proteins by breaking the bonds that link amino acids together, a process known as proteolysis. This is how all of those Bulletproof proteins become free form amino acids that can build muscle or fuel your brain. 

Most people unfortunately produce too little hydrochloric acid (including those with conditions like ulcers and heartburn) and struggle to digest protein and carbohydrates. Taking betaine HCL with meals can be a very valuable biohack for assisting digestion during this phase — allowing the body to better absorb macronutrients and critical micronutrients like vitamins, minerals, peptides and other critical building blocks. 

HCL is also a natural disinfectant so that if there are any pathogens like parasites or harmful bacteria on your food, they are killed before making it further into the digestive process. If you’re not making enough, supplementing is essential. 

Stage 4: Absorption

As food enters the small intestine, the process shifts to absorption — and this is where your microbiome plays a critical role. Friendly microbes in your gut can actually further stimulate enzymes to help break down any food that wasn’t fully processed earlier. 

In fact, several studies have shown that these bacteria can multiply within 24 to 48 hours in the small intestine in response to consumption of high-fat foods, something very common on a Bulletproof or ketogenic diet. The findings from this work suggest that these microbes facilitate production and secretion of digestive enzymes into the small bowel.

Research has shown that sufficient levels of good bacteria in the right balance, will help nutrient absorption — from macronutrients like protein and fats, to micronutrients such as iron and magnesium. Human studies have shown that higher levels of prebiotics, probiotics, and synbiotics in the diet positively affect mineral absorption, bone mineral content, and bone structure.

As we discussed on Bulletproof Radio episode 515 with Dave, this is also why transient or “opportunistic” probiotics — which you might find in cultured foods or certain probiotic supplements — can be so valuable. Their role is not to colonize the gut, but rather, to assist in the digestion and absorption process.

Naveen Jain’s Viome testing has found that few, if any, probiotics successfully colonize or remain in the gut to repopulate with good bacteria after consumed. Our native probiotic levels are determined more by what we eat (and what we avoid) than the probiotic supplements we take. The best plan of action is to eat a variety of foods, especially vegetables for microbial diversity, and combine that with a probiotic based on how well it helps you breakdown your food. That way, your gut is better able to help rebalance itself. 

Stage 5: Elimination

The Ultimate Guide To Poop_If you’re constipatedOnce you have maximized the breakdown and absorption of your food, whatever remains is ready to be eliminated as waste. Here, any undigested food material enters the colon, where most of the water present in the foods consumed will be reabsorbed. This is also why consuming water-rich vegetables is helpful for digestion and overall hydration.

Probiotics continue to play a role in the colon, helping to further absorb nutrients and aid in the elimination process. Peristaltic movements, the same process that your esophagus uses to move food from mouth to stomach — continues to help move the semi-solid waste through the colon. 

At this stage, your rectum expands in response to storage of fecal matter. Have you ever wondered why you get the urge to eliminate when you do? The rectum triggers the signals that create that “gotta go” feeling. Using peristaltic movements of the rectum, waste is ultimately eliminated through the anus, completing the digestive process. 

The success of this process often has a lot to do with the stages before it — in other words, with adequate enzymes, hydrochloric acid, and digestion-enhancing probiotics — less undigested food will make it to the colon. Toxins are reduced. And elimination is cleaner and more complete. 

Digestion Biohacked

When you decide to take control of your biology, you spend a lot of time and attention biohacking different processes in the body, from energy production to muscle-building to sleep — and beyond. But the process of digestion is so central to your health and everything that happens in your body — it’s worth devoting time and energy to upgrading it. 

Understanding and mastering these five stages of digestion will help you upgrade your ability to breakdown food completely, absorb more nutrients, remove waste, and feel your best. 

It’s one of the most noticeable upgrades you can possibly make to your lifestyle and health. 

Want to know even more, have some questions that you’d like to ask? Join Wade and Matt at MEET THE HACKER NIGHTS, November 13 & 14th, which will be held at Upgrade Labs:

Meet the Hacker at Santa Monica: How to Fix and Optimize Your Digestion:

Meet the Hacker at Beverly Hills: How to Fix and Optimize Your Digestion:

If you can’t join biOptimizers there, stop by at their booth at the 7th Annual Upgrade XP conference March 27-29, 2020!




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