Your Questions,
Answered by Someone
Who's Read the Studies.

A clean colonoscopy rules out structural pathology — polyps, IBD, colorectal malignancy. It tells us nothing about microbial composition, mucosal integrity, digestive enzyme sufficiency, or the enteric nervous system's functional state. These are clinical nutrition questions, not gastroenterology questions.

The gap between "nothing structurally wrong" and "fully functional" is where most of my clients live when they first contact me. We fill that gap with functional lab work the gastroenterology workup doesn't include.

For microbial composition: meaningful shifts typically appear in stool analysis at the 6–8 week mark following a targeted prebiotic and dietary intervention. Symptom relief often precedes that — clients frequently report a noticeable reduction in bloating and transit irregularity within 10–14 days of removing the specific fermentable substrates that their panel identified as problematic.

The honest answer is that timeline depends entirely on what we're treating. Dysbiosis responds faster than intestinal permeability. Permeability responds faster than a motility disorder. I give clients a specific forecast at the end of their first session, based on their actual data.

"Fueled correctly by every standard protocol" is doing a lot of work in that question. Standard endurance fueling protocols are population averages. They assume a particular rate of glycogen depletion, a particular fat oxidation capacity, and a particular gut tolerance for mid-exercise carbohydrate. Most competitive amateur athletes have at least one of these variables that sits meaningfully outside the average.

The mile-18 bonk specifically often implicates one of three things: insufficient fat oxidation capacity (the body can't switch fuels efficiently, so it hits the glycogen wall hard), gut dysbiosis that impairs mid-race carbohydrate absorption, or a sodium-fluid balance issue that degrades substrate delivery to working muscle.

We test fat oxidation capacity via a fasted metabolic rate assessment, assess gut function via stool analysis, and map your sodium losses via sweat patch testing. Then we build a protocol from your actual data. The answer to why you bonk is in there.

For recreational athletes: marginal. For competitive amateurs training 12–20 hours per week: material and sometimes decisive. The research on nutrient timing is most robust at training volumes above roughly 10 hours per week — which is exactly where most of my athlete clients live.

The specific levers: protein distribution across the day (not just total intake) has a demonstrated effect on muscle protein synthesis. Carbohydrate periodization — matching carbohydrate availability to training demand on a session-by-session basis — improves both adaptation and performance at higher training volumes. These are not marginal. They're structural.

Quantity and quality are different variables. "Eating enough" usually means meeting caloric demand. It may not mean meeting micronutrient demand — which scales with training volume in ways most athletes and coaches don't account for.

Magnesium demand increases significantly under heavy training load. Zinc losses via sweat are meaningful at high volumes. Iron turnover accelerates with high-impact training (footstrike hemolysis is real and underdiagnosed in distance runners). Vitamin D's role in muscle recovery and immune function is well-established and frequently deficient in athletes training indoors.

Slow recovery on adequate calories almost always has a micronutrient fingerprint. A comprehensive panel reads it clearly.