“Why does my plan give me extra rice on Tuesday but not on Sunday?” It’s one of the most common questions we get from members, and it deserves a better answer than “because the app said so.” The honest answer fits on a phone screen, and getting it right is the difference between a member who trusts their plan and one who quietly ignores it.
This post covers the science behind training-day carbs, where the research is strong and where it’s oversold for everyday gym members, and a one-screen explanation you can send as-is.
The one-screen explanation
Here’s the version we’d put in front of a member. Read it first, then we’ll unpack why each line is there.
- Carbs are fuel for hard work. Your muscles store them and burn through them fastest during intense or long sessions.
- Training days get a bit more. Mostly in the meals before and after your session, so you train well and recover well.
- Rest days get a bit less. Not zero, not a punishment. You just need less fuel when you’re not working hard.
- Protein stays the same every day. It’s rebuilding muscle whether you trained today or not.
That’s it. Four lines, no grams, no jargon. Everything below is for you, the coach, so you can answer the follow-up questions with confidence.
Why carbs follow the work
The idea has a name in sports nutrition: “fuel for the work required”. The framework, set out by researchers at Liverpool John Moores University, argues that carbohydrate should be matched to the demands of each session rather than held constant every day. Hard sessions run on muscle glycogen; easy days and rest days don’t need nearly as much.
The mainstream guidelines reflect the same logic. The joint position statement from the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada scales daily carbohydrate to training load, from 3–5 g/kg for light, skill-based training up to 8–12 g/kg for extreme loads of four to five hours a day. The 2025 update to this thinking from the same research group goes further, framing intake as something to adjust “day by day and meal by meal” around the intensity and goals of each session.
- Light training: 3–5 g of carbs per kg of body weight per day
- About an hour a day, moderate: 5–7 g/kg per day
- One to three hours, high intensity: 6–10 g/kg per day
Those numbers come from athletes. That context matters, and it’s where a lot of coaching goes sideways.
What the research says for your members
Most boutique and studio members aren’t training for hours a day. They’re doing 45 to 60 minutes, three or four times a week, often with a body composition goal. For them, the swing between training and rest days is real but modest: think an extra fist-sized portion of rice or potatoes around a session, not a different diet.
Session type matters too. A 2022 systematic review of 49 studies on carbohydrate and resistance training found that 39 showed no significant performance benefit from extra carbs. Benefits showed up mainly in high-volume sessions (more than about 10 sets per muscle group), when lifters trained after fasting for four hours or more, or when they trained twice a day. The authors’ practical floor was modest: at least 15 g of carbohydrate and 0.3 g/kg of protein within three hours of training.
Conditioning-heavy and hybrid formats (intervals, circuits, the HYROX-style classes many studios now run) lean harder on glycogen than a straight strength session. Those are the days where the extra carbs earn their place.
Carbs aren’t a reward for training. They’re the fuel bill for it, and the bill depends on the session.
What most coaches get wrong
Copying elite protocols
Periodization research is often done on professional cyclists and runners. The 2025 periodization review describes high-load days in elite cycling reaching 13–16 g/kg. Members see those headlines, coaches borrow the language, and suddenly a three-day-a-week member thinks they need a “carb-loading” strategy. They don’t.
Turning rest days into low-carb days
“A bit less” quietly becomes “almost none,” especially for members chasing fat loss. That backfires. The 2023 International Olympic Committee consensus on Relative Energy Deficiency in Sport notes that low carbohydrate availability can speed up the development of REDs, which is tied to poorer bone health, immunity and iron status. Recreational members aren’t elite athletes, but an aggressive deficit plus hard training plus slashed rest-day carbs is a pattern worth catching.
Forgetting the GLP-1 member
More members are now training while on GLP-1 medications, with appetite that can drop sharply. The 2025 joint advisory from four lifestyle medicine, nutrition and obesity societies prioritizes adequate protein, strength training and nutrient-dense food to protect muscle. For these members, the training-day bump should be easy to eat (a banana, yogurt, toast) and protein comes first. Cutting carbs further on rest days is rarely the problem to solve.
Over-explaining
Glycogen thresholds and g/kg tables are useful to you. To a member at 7am, they’re noise. If your explanation needs a second screen, it’s too long.
How to build the plan behind the screen
The one-screen message only works if the plan underneath is simple enough to match it. A structure that holds up for most members:
- Set protein first and keep it constant across the week.
- Set a rest-day carb baseline that supports their goal without dropping to near-zero.
- Add a training-day bump of roughly 25–50 g for a standard class, more for long or interval-heavy sessions, placed in the pre- and post-session meals.
- Let fat flex slightly so weekly calories stay on target.
Those bump sizes are our coaching starting point, not a research number; adjust from how members feel and perform. For members fitting in an early session, the ISSN position stand on nutrient timing supports combining carbohydrate and protein after training to help restore glycogen and support recovery, which is easier to sell as “have breakfast after class” than as a macro target.
In Mahdofit, nutrition plans can shift carbs automatically when a session is scheduled or a workout syncs from a wearable, so the member just sees “training day” at the top of their plan instead of doing math. Whatever tool you use, keep that member-facing label as plain as the screen above.
Handling the follow-up questions
Members will push back, usually with one of three questions. “Won’t carbs make me gain fat?” Not when total intake fits the goal; the timing just puts them where they’re most useful. “Can I save my rest-day carbs for the weekend?” Occasionally, but the point is fueling sessions, so the trade only works if it doesn’t gut a training day. “Do I need sports drinks?” For a typical hour-long class, usually not. Water and a normal meal before are enough.
The deeper message behind every answer is the same: the plan follows their training, so when their week changes, the plan should too.
The short version
- Carbs scale with training load: more on hard or long days, a bit less on rest days, never near-zero.
- For most studio members, the swing is modest: an extra portion around the session, not a new diet.
- Prioritize carbs for high-volume, interval-heavy or hybrid sessions; straight strength work needs less.
- Keep protein constant, and protect fuel and muscle for members in a deficit or on GLP-1 medications.
- Explain it in four plain lines on one screen, and keep the g/kg tables for yourself.
