This issue is powered by The Performance Nutrition Network
Dear Performance Nutrition Leaders,
This week: Dr Sam Impey on the 18 hours between Grand Tour stages, the latest news, and Maurten’s M.Test protocol.
💡 EXPERT OPINION
From the finish line to the next start, Dr Sam Impey sees Grand Tour recovery as “an 18-hour stopwatch”.
Speaking with Dr James Morehen for the Performance Nutrition Network, the Hexis co-founder and chief scientific officer framed the question plainly: can a practitioner get a rider race-ready again from a fuelling standpoint in 18 hours?
Impey said teams drip-feed carbohydrate from the moment a stage finishes until the rider goes to bed, usually at 1.2–1.5g per kg of body mass per hour for the first three hours. Transfers complicate that window, so meals are pre-packaged and pre-weighed against predicted expenditure before the stage ends.
The plan then moves with the data. If a rider expends an extra 150–300 calories, Impey said that can be captured and acted on within 20 minutes of the finish, rather than discovered the next day.
He also described rehearsing 7,000–9,000-calorie days during altitude camps, depending on the rider’s body mass, so the largest race-day intake already has a reference point.
The change is not simply more carbohydrate. In Impey’s account, it is the speed at which practitioners can detect a gap and amend the plan before the bus reaches the hotel.
Watch the recording via the Performance Nutrition Network →
📈NEWS
Max Haskell appointed performance nutritionist at AFC Bournemouth
Ashlyn Mydloski appointed Spartans Fuel intern with the Michigan State University Football team
sportscotland is hiring a Performance Nutritionist (£47,699–£54,569) — the 12-month maternity cover closes 27 August
Team GB is hiring an HQ Lead for Performance Nutrition for LA2028 — applications close 31 August
Millwall FC is hiring a full-time Performance Nutritionist across first-team and academy programmes — applications close 31 August
Kendal Mint Co launched GEL X with 45g carbohydrate and 200mg sodium per 70g gel
GetPRO Professional opened its 2026 Grassroots Sports Nutrition Grants — early-career UK practitioners can apply for up to £2,000 by 30 September
Arla Foods Ingredients roll out consumer research project in partnership with Alistair Brownlee’s company truefuels
Have an industry update you’d like to share? Drop us an email → [email protected]
💡PERFORMANCE TECH
Maurten has turned carbohydrate oxidation into a four-hour case study.
In an M.Test published on 15 August, Maurten reports testing professional triathlete and medical student Matthew Marquardt on two separate days. Each protocol paired 180 minutes of cycling at roughly 300W with a one-hour treadmill run at 15.5km/h. Marquardt consumed 160g carbohydrate per hour on day one and 200g/h on day three, delivered through carbon-13-labelled Maurten Drink Mix.
From 90 minutes, breath bags were collected every 20 minutes. The isotope allowed the testing team to distinguish exogenous carbohydrate — fuel consumed during exercise — from endogenous stores. Oxygen and carbon dioxide were also measured intermittently, with lactate sampled every 30 minutes.
Maurten reports exogenous oxidation reached around 135g/h at the lower intake and 170g/h at the higher intake, with efficiency remaining near 85%. The brand therefore proposed 160–200g/h on the bike and at least 120g/h on the run for Marquardt.
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