Carb periodisation: matching your carbs to the training you actually did

Most people eat roughly the same carbohydrate intake every day, whether they did a hard interval session or sat at a desk. Athletes and their nutritionists have largely moved past that: the modern principle is carbohydrate periodisation — matching intake to the day's training demand rather than applying one flat number.

'Fuel for the work required'

Impey and colleagues (2018, Sports Medicine) framed the idea as 'fuel for the work required': high-intensity and long-duration sessions run on glycogen, so the days around them warrant more carbohydrate, while low-intensity or rest days need less. Deliberately training some low-intensity sessions with lower carbohydrate availability ('train low') can amplify certain endurance adaptations — but hard, high-quality sessions should be well fuelled, because under-fuelling them just makes the session worse.

Carbs are not good or bad — they are a fuel you match to demand. A hard session earns them; a rest day doesn't need the same amount.

The practical structure

In practice this means higher carbohydrate on training days — especially around the session, when insulin sensitivity is highest and glycogen replenishment is most efficient — and lower carbohydrate on rest days, with the calories often redistributed toward protein and fat to preserve satiety. Protein stays high every day regardless; it is carbohydrate that flexes with the workload. This is not carb-cycling for its own sake — it is aligning intake with genuine physiological demand.

How Misi builds this in automatically

Misi generates its 7-day plans against your training schedule, splitting macro targets into training-day and rest-day profiles — training days carry higher carbohydrate and calories, rest days pull them back — so periodisation is the default, not something you have to hand-calculate. The Insights energy-balance chart then shows your logged intake against the correct target for each day, with separate reference bands for training and rest, so you can see whether you are actually fuelling your hard days and easing off on your easy ones.

The practical takeaway

If your training quality dips or your recovery feels flat, check whether you are under-fuelling your hardest sessions. And if fat loss has stalled, a genuine rest day is the right place to trim carbohydrate — not the day before a demanding workout you need to perform in.

Misi is a coaching and wellness platform, not a medical service. Athletes with specific clinical or performance needs should work with a registered sports dietitian.