Digestive Health

What is actually happening in your gut

These five conditions look different from the outside. Reflux is not colitis, and bloating is not bleeding. But they run on a small number of shared mechanisms, and food touches every one of them.

Your gut lining is protective, and it can be worn down

The wall of your intestine is covered by a mucus layer that keeps its contents at a safe distance from the tissue underneath, and sealed by tight junctions that control what gets absorbed and what does not. That system is your first line of defence.

Several things in a modern diet degrade it. Emulsifiers and additives thin the protective mucus layer, letting contents make direct contact with the wall. Gluten triggers release of zonulin, the protein that regulates how tightly the lining is sealed. Lectins and saponins in grains and legumes bind to gut cells and disrupt barrier function. Once the barrier is compromised, bacterial products and food proteins cross into tissue where they provoke inflammation, and inflammation degrades the barrier further.

That loop is at the centre of inflammatory bowel disease, and it plays a role in the conditions further down this page too.

Fermentation is what causes most of the bloating, gas, and pressure

Some carbohydrates are poorly absorbed in the small intestine. They travel onward to the colon, where bacteria ferment them, producing hydrogen, methane, and carbon dioxide. They are also osmotically active, meaning they pull water into the gut.

Gas plus water in a confined space produces exactly what you would expect: distension, bloating, cramping, urgency, and pain. In a sensitive or inflamed gut, or one where bacteria have colonised the small intestine, this is the difference between a comfortable day and a ruined one.

This is the single most modifiable driver of digestive symptoms, and reducing fermentable carbohydrate is the intervention with the best evidence behind it in this whole area.

Your microbiome responds to what you feed it

The bacterial population in your gut shifts based on the substrate available. Diets high in sugar and refined carbohydrate favour species that thrive on them, and that shift is associated with digestive symptoms, inflammation, and further barrier disruption. Artificial sweeteners and emulsifiers have their own documented effects on bacterial balance.

Change the inputs and the population changes. That is not a fringe idea, it is one of the more established findings in gastroenterology.

Inflammation ties it together

Systemic inflammation both drives and is driven by gut trouble. This is where lowering carbohydrate contributes something separate from removing trigger foods. When your body shifts toward burning fat it produces beta-hydroxybutyrate, a ketone body that directly inhibits the NLRP3 inflammasome, one of the main switches your immune system uses to generate inflammatory signals. A systematic review and meta-analysis of randomized controlled trials found low-carbohydrate diets significantly lowered TNF-alpha and IL-6, two of the messengers driving inflammation in the gut.

Which is why the approach works

Take pressure off the barrier, cut the fermentation load, change what you are feeding your microbiome, and lower the inflammatory signal. Then, once your gut has settled, add foods back one at a time and find out precisely what you can tolerate.

That last step is the one most people never get to. It is why so many people with digestive conditions end up on a permanently narrow diet built from guesswork, avoiding things that were never the problem while still eating the thing that was.

Crohn’s Disease

What Crohn’s disease is

Crohn’s disease is a form of inflammatory bowel disease in which the immune system attacks the lining of the digestive tract. It can occur anywhere from mouth to anus, most often at the end of the small intestine, and it affects the full thickness of the bowel wall. Inflamed sections often sit between stretches of healthy tissue, and it typically runs in cycles of flare and quiet.

Crohn’s disease symptoms

• Abdominal pain and cramping, often in the lower right
• Persistent or urgent diarrhea
• Blood in the stool
• Fatigue that rest does not resolve
• Unintended weight loss and reduced appetite
• Fever during flares
• Mouth sores
• Pain or drainage near the anus
• Nutrient deficiencies from impaired absorption

What drives Crohn’s disease

• A worn-down gut barrier. When the mucus layer thins and the lining becomes permeable, bacterial products and food proteins reach tissue that should never encounter them, and the immune system attacks the bowel wall.
• Microbiome imbalance. Reduced bacterial diversity and a shift toward inflammatory species are consistently found in Crohn’s and appear to sustain the cycle.
• Diet. Emulsifiers, additives, and refined carbohydrate degrade the protective mucus layer and are associated with higher rates of inflammatory bowel disease.
• Fermentation load. Poorly absorbed carbohydrates produce gas and draw water into a bowel that is already inflamed and narrowed, which is why many people with Crohn’s find certain healthy foods intolerable.
• Smoking. Associated with more severe disease and higher relapse rates, and one of the clearest things within your control.
• Genetic susceptibility. More than 200 variants have been linked to inflammatory bowel disease. They raise your risk. They do not decide your outcome.

How Revero treats Crohn’s disease

In Crohn’s, every meal makes direct physical contact with inflamed tissue. That makes food an unusually powerful lever, and it is why dietary change can produce results here faster than most people expect.

Your care team removes the food groups that provoke immune activity and degrade the gut lining, then reduces the fermentable carbohydrates producing gas, pressure, and pain in an already irritated bowel. During a flare, your plan is adjusted to give the gut less to work against while it heals. Lowering carbohydrate adds a second layer, shifting your metabolism into a state that suppresses inflammatory signalling directly.

The research is striking. In a Scripps clinical study of an elimination protocol in inflammatory bowel disease, participants had lived with their disease for an average of 19 years and nearly half were on biologic therapy that was not adequately controlling it. Within six weeks, 73% had their disease activity fall into the inactive range, and held it through the maintenance phase. A follow-up study found significant improvements in quality of life alongside. A separate randomized trial reducing fermentable carbohydrates found 81% of participants improved compared with 46% on their usual diet.

Around that plan sits the clinical care that makes it hold. Your provider reviews your baseline labs before you begin and follows hs-CRP at three, six, and twelve months, so the question of whether inflammation is actually falling gets a real answer rather than resting on how you felt this week. You track abdominal pain, stool frequency, blood, and fatigue daily on the same validated questionnaire a gastroenterologist would use.

Your coach is there every day, which counts for most during a flare, when every meal feels like a gamble and what you need is someone to tell you what is safe to eat tonight. As your symptoms and markers settle, your provider can begin reducing medication, gradually and with your agreement.

Among Revero patients with Crohn’s disease, average scores on the IBD-Control-8 questionnaire rose from 10.0 to 16.0 in three months. That questionnaire runs from 0, meaning worst control, to 16, meaning best control, and a score of 13 or above indicates disease that is well controlled. Our patients moved from below that line to well above it.¹ In an independent Harvard Medical School affiliated study, 97% of participants with gastrointestinal conditions reported their condition resolved or improved.³

Ulcerative Colitis

What ulcerative colitis is

Ulcerative colitis is the other main form of inflammatory bowel disease. It is confined to the colon and rectum, affects the innermost lining rather than the full bowel wall, and spreads continuously from the rectum upward. The underlying process is an immune attack on the gut lining that produces ulceration, bleeding, and inflammation.

Ulcerative colitis symptoms

• Diarrhea, frequently with blood or mucus
• Urgency, and the sensation of needing to go without being able to
• Abdominal pain and cramping, often on the left
• Fatigue and anemia from ongoing blood loss
• Unintended weight loss
• Waking at night to use the bathroom
• Reduced appetite

What drives ulcerative colitis

• Loss of the protective mucus layer. The colon relies heavily on mucus to keep bacteria at a distance from the wall. Emulsifiers and additives in processed food thin that layer, and once contact is made, inflammation follows.
• Microbiome imbalance. Shifts in bacterial populations are consistently found in ulcerative colitis and appear to sustain the inflammatory cycle.
• Fermentation and osmotic load. Poorly absorbed carbohydrates draw water into the colon and produce gas, which drives urgency, cramping, and frequency in a colon that is already inflamed.
• A permeable gut lining. As the barrier weakens, material crosses into tissue and provokes an immune response that becomes self-sustaining.
• Immune dysregulation and genetics. Susceptibility runs in families, and once the process starts it tends to perpetuate itself.

How Revero treats ulcerative colitis

Ulcerative colitis responds to this approach as well as any condition we treat, and there is a clear reason for that. When inflammation is confined to the colon and driven by what passes through it, changing what passes through it is a direct intervention rather than an indirect one.

Your plan removes the foods that provoke immune activity and strip the mucus layer protecting the colon wall, then reduces the fermentable carbohydrates driving gas, urgency, and cramping. Lowering carbohydrate raises ketone levels that suppress inflammatory signalling through a separate pathway. During flares your plan is adjusted so the colon has less to contend with while it heals.

The Scripps elimination protocol study included patients with ulcerative colitis, with 73% of participants overall reaching inactive disease within six weeks despite an average of 19 years living with it. A randomized trial reducing fermentable carbohydrates found 81% improved compared with 46% on their usual diet.

Your provider watches two things that matter specifically here: hs-CRP for inflammation, and a complete blood count, because steady blood loss produces the anemia behind much of the fatigue and it is easy to miss. Both are checked at baseline and at each follow-up.

Daily, you log urgency, bleeding, frequency, and pain, and your coach sees it in real time. Patients consistently tell us the most valuable part is having someone to message on a bad morning rather than waiting months for the next appointment. As your scores improve, your provider can start reducing medication, deliberately and with your consent.

Ulcerative colitis has produced the largest change of any condition we track. Among Revero patients, average scores on the IBD-Control-8 questionnaire rose from 6.7 to 15.3 in three months. That questionnaire runs from 0, meaning worst control, to 16, meaning best control, and a score of 13 or above indicates disease that is well controlled. Our patients started well below that line and finished comfortably above it, scoring 96% of the best result the questionnaire allows.¹ In an independent Harvard Medical School affiliated study, 97% of participants with gastrointestinal conditions reported their condition resolved or improved.³

Irritable Bowel Syndrome (IBS)

What IBS is

Irritable bowel syndrome is diagnosed when you have persistent abdominal pain and altered bowel habits without visible damage on tests. It is usually described as a functional disorder, meaning the structure looks normal but the function is not.

That description leads a lot of people to feel dismissed, as though normal test results mean nothing is really wrong. Something is really wrong. The gut is a complex system, and it can malfunction without producing visible lesions, in the same way a nerve can misfire without anything showing on a scan.

IBS is generally grouped by predominant pattern: diarrhea, constipation, or a mix of both.

IBS symptoms

• Abdominal pain or discomfort, often relieved by a bowel movement
• Bloating and visible distension, frequently worse as the day goes on
• Diarrhea, constipation, or alternating between them
• Urgency
• Mucus in the stool
• The sensation of incomplete emptying
• Symptoms that flare after eating, under stress, or around the menstrual cycle
• Fatigue and poor sleep

What drives IBS

• Fermentable carbohydrates. The clearest and most actionable driver. Poorly absorbed carbohydrates ferment in the colon, producing gas, and pull water in osmotically. In a sensitive gut this is enough to produce severe pain, bloating, and urgency from foods that most people digest without noticing.
• Visceral hypersensitivity. People with IBS perceive normal gut sensations as painful. The volume of gas may be ordinary; the response to it is not. This is why reducing the trigger matters so much, since the sensitivity itself is harder to change.
• Microbiome imbalance. Altered bacterial populations are common in IBS and influence both fermentation and gut signalling.
• The gut-brain axis. The gut and brain are in constant two-way communication, which is why stress reliably worsens symptoms. This is real physiology, not a suggestion that symptoms are imaginary.
• Post-infectious onset. A meaningful proportion of IBS begins after a bout of gastroenteritis, which alters both the microbiome and gut sensitivity.
• Low-grade inflammation and barrier changes. Increasingly documented in IBS despite the absence of visible damage.

How Revero treats IBS

IBS is the condition where dietary treatment has the strongest evidence base of anything in this area, and where most people have never had it done properly.

Reducing fermentable carbohydrate directly cuts the gas and osmotic load that produce the bloating, distension, and pain. Removing the foods that provoke immune activity and irritate the lining addresses the low-grade inflammation and barrier changes now recognised in IBS. And because the plan removes sugar and refined carbohydrate, the microbiome shifts away from the species that thrive on them.

A systematic review and network meta-analysis of dietary interventions in IBS published in The Lancet Gastroenterology and Hepatology found that of all the dietary approaches studied, reducing fermentable carbohydrate has the most evidence behind it, and it was the only intervention superior to a habitual diet for bloating and distension.

The part that is usually missing is what comes next. Reducing fermentable carbohydrate is a diagnostic phase, not a life sentence, and staying on it indefinitely is neither necessary nor good for your microbiome. Your care team walks you through structured reintroduction so you finish knowing your specific triggers and eating as broadly as you can.

The clinical side of this is what turns a diet into a diagnosis. Your provider runs a full baseline panel first, because IBS is a diagnosis of exclusion and it is worth being certain nothing else is driving your symptoms. From there, you log pain, bloating, urgency, and stool pattern every day.

That daily log is the whole engine of this process. Your coach reads it alongside you and helps connect what you ate to what happened, which is the piece almost nobody manages alone, because the reaction often arrives a day later than the meal. By the end of reintroduction you have a specific, tested list rather than a long list of suspicions.

In our survey of more than 11,000 people following a low-carb high-protein diet, 95% of those with gastrointestinal conditions reported improvement.² In an independent Harvard Medical School affiliated study, 97% of participants with gastrointestinal conditions reported their condition resolved or improved.³

Gastroesophageal Reflux Disease (GERD)

What GERD is

GERD occurs when stomach contents move back up into the esophagus often enough to cause symptoms or damage. The esophagus, unlike the stomach, has no protective lining against acid, which is why reflux burns.

The valve at the bottom of the esophagus is meant to stay closed between swallows. In GERD it relaxes when it should not, or pressure from below overcomes it.

GERD symptoms

• Heartburn, particularly after meals or when lying down
• Regurgitation of food or sour liquid
• Chest pain
• Difficulty swallowing or the sensation of food sticking
• Chronic cough, hoarseness, or throat clearing
• A lump-in-the-throat sensation
• Disrupted sleep from night-time symptoms
• Dental erosion from repeated acid exposure

What drives GERD

• Carbohydrate and fermentation pressure. This is the driver most people have never heard about, and it is the one with the best supporting evidence. Fermentable carbohydrate produces gas in the upper digestive tract, and that gas increases pressure below the valve, which promotes reflux. It is a mechanical problem with a dietary cause.
• Excess weight, particularly around the middle. Abdominal weight raises pressure on the stomach and pushes contents upward.
• Meal size and timing. Large meals and eating close to bedtime both increase reflux, for straightforward mechanical reasons.
• Alcohol, and certain foods and medications. Several relax the valve or increase acid production.
• Hiatal hernia. A structural contributor in some people, which is worth identifying because it changes what to expect from treatment.
• Smoking. Reduces valve pressure and saliva production, both of which normally protect the esophagus.

How Revero treats GERD

Acid-reducing medication works by making your stomach contents less acidic. It does not reduce how often reflux happens, which is why symptoms return when the medication stops and why long-term use is so common.

Our approach targets the reflux itself. Cutting fermentable carbohydrate reduces the gas production driving pressure upward. Losing weight around the middle reduces the mechanical load on the stomach. Removing the foods that relax the valve or irritate the esophagus removes a further layer.

The evidence for this is better than most people realise. A systematic review and meta-analysis of dietary interventions in GERD found that low-carbohydrate diets significantly reduced the amount of time the esophagus was exposed to acid, and that they were the intervention with a demonstrable effect. In a randomized controlled trial of 98 patients, modifying dietary carbohydrate significantly changed both acid exposure time and the number of reflux episodes measured objectively. And in a study using 24-hour pH monitoring, participants starting a very low-carbohydrate diet saw acid exposure fall by half and symptom scores improve significantly within six days.

Six days. That is one of the fastest responses to any dietary change in any condition we treat.

Your provider runs a full baseline panel including metabolic markers, since weight and insulin resistance feed the mechanical side of reflux, and follows them as your plan takes effect. You track heartburn, regurgitation, and how much your sleep is being disrupted, which is often the symptom that matters most to people and the one least often asked about.

Your coach works on the practical levers that make a real difference in reflux: meal size, how late you eat, and what your evenings look like. And if coming off a long-term acid reducer is your goal, your provider manages that taper against your daily symptom log, which is what keeps rebound acid from sending you straight back onto it.

In our survey of more than 11,000 people following a low-carb high-protein diet, 95% of those with gastrointestinal conditions reported improvement.² In an independent Harvard Medical School affiliated study, 97% of participants with gastrointestinal conditions reported their condition resolved or improved.³

Small Intestinal Bacterial Overgrowth (SIBO)

What SIBO is

SIBO occurs when bacteria that belong in the colon colonise the small intestine in large numbers. The small intestine is where you absorb most of your nutrients, and it is meant to have relatively few bacteria. When that changes, food starts being fermented before you have absorbed it.

That single fact explains almost every SIBO symptom. Fermentation that should be happening at the end of the process is happening at the start, in a narrower space, closer to nerve endings.

SIBO symptoms

• Bloating, often severe, and typically worse after eating
• Abdominal pain and cramping
• Excessive gas
• Diarrhea or constipation, depending on which gases predominate
• Fatigue
• Nutrient deficiencies, particularly B12 and fat-soluble vitamins
• Unintended weight loss in some cases
• Food intolerances that seem to multiply over time

What drives SIBO

• Fermentable carbohydrate reaching the overgrowth. Bacteria in the small intestine need substrate. Poorly absorbed carbohydrates are exactly that, and every meal containing them feeds the population that is causing your symptoms.
• Impaired gut motility. The small intestine has a cleaning wave that sweeps bacteria downward between meals. When that mechanism is impaired, bacteria stay and multiply. Constant grazing suppresses it, which is why meal spacing matters.
• Low stomach acid. Acid is one of your defences against bacteria colonising the upper gut, which is one reason long-term acid suppression is associated with SIBO.
• Structural and post-surgical changes. Adhesions, strictures, and previous abdominal surgery can create pockets where bacteria accumulate.
• Related conditions. SIBO is common alongside IBS and Crohn’s disease, and frequently explains why someone treated for one of those is not improving.

How Revero treats SIBO

SIBO has a mechanism so direct it is almost mathematical. Bacteria in the wrong place are fermenting carbohydrate you have not yet absorbed. Reduce the fermentable carbohydrate arriving there, and you reduce both the fuel supply and the gas production causing your symptoms.

Your plan lowers total carbohydrate and specifically reduces the fermentable carbohydrates that feed the overgrowth. Removing sugar and refined carbohydrate shifts the bacterial balance away from the species thriving on them.

Many people with SIBO have accumulated a long list of foods they cannot eat, added one bad experience at a time, and still feel unwell. Structured elimination followed by careful reintroduction replaces that list with an accurate one, which usually turns out to be much shorter than the one built by guesswork.

Your provider runs a full baseline panel including B12 and fat-soluble vitamins, which are commonly depleted in SIBO because the overgrowth interferes with absorption before you get to use them. That is also frequently the explanation for fatigue that seems out of proportion to the digestive symptoms. Your provider reviews contributing factors too, including whether long-term acid suppression is keeping the overgrowth in place.

You track bloating, gas, pain, and fatigue daily, and your coach works with you on both the plan and the meal spacing that supports your gut clearing itself between meals. Because SIBO has a tendency to return, that ongoing support is doing more here than in almost any other condition we treat.

In our survey of more than 11,000 people following a low-carb high-protein diet, 95% of those with gastrointestinal conditions reported improvement.² In an independent Harvard Medical School affiliated study, 97% of participants with gastrointestinal conditions reported their condition resolved or improved.³

How your plan actually works

The first phase is about finding answers

We begin by removing the most common triggers together, and reducing the fermentable carbohydrates driving gas and pressure. Not because you will avoid all of it forever, but because while you are eating all of it the signal is buried in noise and nobody, including you, can tell what is actually causing your symptoms.

No blood test answers this reliably. Food sensitivity panels are heavily marketed and are not dependable. Structured elimination followed by careful reintroduction is the most accurate method available, and it is what your care team runs with you.

Then you get your foods back

This is the step most people never reach, and it is the most important one. Once your gut has settled, your care team starts adding foods back one at a time while you keep tracking daily. No reaction, and the food stays. Symptoms return, and you have learned something specific and permanent.

Staying on a very narrow diet indefinitely is not the goal and is not good for your microbiome. Most people finish this process eating considerably more variety than they expected, and knowing exactly which few things they need to avoid.

The plan moves with you

Progressing well, and your care team widens it. In a flare, they tighten it to give your gut less to contend with. Struggling to stay with it, and you tell your coach and it changes. A plan you abandon in week three helps nobody, so we build one you can actually keep.

Medications

You do not stop anything to start with us. You begin your nutrition therapy while continuing everything you currently take, and nothing changes unless your provider recommends it and you agree.

As your symptoms improve, reducing medication becomes a real possibility, whether that is a daily acid reducer or a biologic. Revero uses a structured, stepwise process run by your provider, monitored with lab work and daily symptom tracking, and coordinated with your gastroenterologist. Some of these medications need careful tapering, and having a provider watching your labs and symptoms is exactly what makes reducing them safe.

Many of our patients get there. It happens gradually, with data, and with a physician making the call.

Results

Among Revero patients with inflammatory bowel disease, symptom control on the validated IBD-Control-8 questionnaire improved substantially within three months, with ulcerative colitis patients rising from 6.7 to 15.3 and Crohn’s patients from 10.0 to 16.0 on a scale where 13 or above indicates well-controlled disease. Across all conditions, hs-CRP, a standard marker of systemic inflammation, improved 25%.¹

Patients who entered the program with the lowest quality-of-life scores saw substantial gains across nearly every domain measured, including energy and fatigue, pain, physical functioning, and emotional wellbeing. The people carrying the heaviest burden at the start improved the most.¹

In our survey of more than 11,000 people following a low-carb high-protein diet, 95% of those with gastrointestinal conditions reported improvement, and 79% of those taking medications reported reducing or eliminating them.² In an independent Harvard Medical School affiliated study, 97% of participants with gastrointestinal conditions reported their condition resolved or improved, and 95% reported their overall health improved.³