Nutrition Timing and the 8-10 Week Prep Window

Nutrition Timing and the 8-10 Week Prep Window

Why the first adjustment is usually the right one, and why stacking changes too fast makes physique coaching noisier than it needs to be.

Justin Harris’ simple prep note was to add a serving of Dulcolax daily for the final 8-10 weeks of a prep, because he believed much of the distention came from backed-up digestion and a drier gut, not from some mystery process. The mechanism is plain: slower transit plus reduced water intake can create constipation-related distension. The practical thesis for AI coaching is sharper than the usual “monitor and adjust” advice: make nutrition changes on a schedule that matches the body’s lag time, or you will confuse cause and effect and over-correct the wrong variable.

The coaching problem is not making changes

It is making too many changes before the previous one has had time to show up.

That sounds obvious, but it is where a lot of nutrition coaching gets sloppy. Athletes change carbs, water, sodium, fiber, meal timing, supplements, and sometimes training stress at the same time, then judge the result by how they look or feel 24 hours later. In the context of prep, that is a bad measurement window. Justin’s note about the final 8-10 weeks gives a useful coaching frame: when the gut tends to become more sensitive, you do not need a new experiment every day. You need one controlled change, enough time for it to express, and then a second decision.

Timing matters because the effect is delayed

The body does not update all at once. Digestion, hydration status, and GI comfort can drift over days, not hours. In the message from Justin, the trigger was travel plus slightly lower water intake, and the result was constipation for a couple days. That is the kind of lag coaches have to respect. If a client reports distension after one bad day of intake, the answer is not necessarily to slash food immediately. It may simply be a short-term transit issue that will resolve once water, food volume, and routine normalize.

This is the main reason over-adjustment is dangerous: it compounds noise. If you lower food, add a digestive aid, cut water, and change meal frequency all at once, you cannot tell which lever mattered. When the athlete improves, you do not know what to keep. When they worsen, you do not know what to undo. That is not coaching precision; that is self-inflicted uncertainty.

A prep window is not a permission slip to panic

The note’s useful detail is the timing: “final 8-10 weeks.” That matters because it implies the need for proactive planning, not reactive scrambling. If a client repeatedly gets constipated or distended late in prep, the coach should anticipate the pattern before it becomes a weekly fire drill.

But anticipation is not the same thing as constant intervention. A better sequence is:

1. Identify the recurring pattern.
2. Make one targeted change.
3. Hold it long enough to judge it.
4. Only then decide whether the next change is needed.

That sequence is boring, and boring is good. Most bad prep decisions come from trying to solve a future problem too early. The athlete wakes up bloated, the coach sees a bad check-in, and suddenly there are four new instructions. The result is usually more confusion, not more control.

The coach should separate signal from background noise

Justin’s comment about travel is the kind of detail that should make coaches cautious. Travel changes hydration, schedule, meal timing, movement, and stress. Any one of those can alter digestion. So if a client is already in a sensitive phase, the correct response is not to assume the physique changed overnight. The correct response is to ask whether the issue is transient background noise.

This is where AI coaching can actually help if it is used correctly. A good system should make the coach slower to overreact, not faster. It should flag trends, compare the current check-in to prior weeks, and preserve the context around water intake, travel, and routine changes. In other words, it should help the coach see that a single distended day is not the same thing as a real protocol failure.

The evidence-aware rule: change one variable at a time

The strongest lesson from the source material is not about a specific product or a magic fix. It is about decision structure. If lower water on the drive back from KC produced constipation for a couple days, that is a reminder that small shifts can have delayed consequences. If bigger athletes in prep dry out faster and get backed up more easily, then the late-prep plan should emphasize consistency first and adjustments second.

For coaches, that means less tinkering.

It means not making nutrition changes just because a check-in looks slightly off.

It means not stacking multiple fixes to impress yourself with activity.

It means waiting long enough to learn whether the athlete actually needed the change.

That does not mean being passive. It means being deliberate.

What this looks like in practice

A practical AI coach would handle timing like this:

• Keep intake stable when possible so the baseline is readable.
• Treat travel, water changes, and schedule shifts as confounders.
• Use a single adjustment and let it run long enough to see its effect.
• Reassess based on the next few days, not the next few hours.
• Escalate only when the pattern repeats.

That process does two things at once. It reduces unnecessary intervention, and it protects the coach from attributing every look change to the last variable touched. In prep, that matters because the athlete’s margin for error shrinks as the timeline gets closer to show day.

The real coaching skill is restraint

AI coaching often gets sold as faster answers and more automation. The better use case is more disciplined timing. The best system is not the one that responds to every data point immediately; it is the one that knows when to wait.

Late-prep nutrition is a good test of that discipline. If the athlete is constipated, distended, and sensitive, the knee-jerk response is to keep changing things until something feels different. The better response is to make the first change, watch it over an appropriate window, and resist the urge to stack the second change before the first one has had a chance to work.

That is the falsifiable coaching thesis here: when you space nutrition changes to match physiologic lag, you get clearer feedback and fewer unnecessary corrections; when you chase same-day reactions, you create more noise than signal.

Sources Used

• raw/_consumed/2026-05-31/kahunas-export/2026-05-31-w19-24m/clients/david_lamartina___members-tlssnsjthkmnhfqcscszce25acz_vhdm_x2_xdlpx_i.json
• raw/Justin_TT1.txt