Carbohydrates in Training: Simple vs Complex, Quantity and Timing

Carbohydrate remains the most demonized and misunderstood macronutrient in gyms. This article covers quantity, type, timing and dispels the main myths.

Role of carbohydrates in training

Direct answer: Carbohydrate is the main fuel for high-intensity training. It is stored as glycogen in muscle and liver. In strength training, partial glycogen depletion reduces performance and volume capacity. Adequate replacement is essential for recovery and the next workout.

Total amount per day

Profile	Range
Sedentary	2 a 3 g/kg/dia
Moderate strength training	3 a 5 g/kg/dia
High volume strength training	4 a 6 g/kg/dia
endurance athlete	5 a 8 g/kg/dia
Heavy competitive athlete	7 a 10 g/kg/dia

Base: ISSN, ACSM, Thomas et al. 2016.

Simple vs complex: how much does it matter

Physiological difference

• Simple: glucose, fructose, sucrose, maltodextrin; fast absorption
• Complexes: starches (rice, potatoes, oats, pasta); slower absorption
• Fibrous: vegetables; very slow absorption, lower energy contribution

Practice

Throughout the day, with a diet that includes adequate fiber (25 to 38 g/day), the “simple vs complex” distinction does little to change body composition or performance. What matters:

• Total quantity
• Enough fiber for gut health
• Do not generate extreme glycemic peaks outside of the training context

Strategic timing

Pre-workout (2 to 3 hours before)

• 1 to 2 g/kg
• Sources: rice, potatoes, oats, bread, fruits
• Allows complete digestion and stable blood glucose peak

Immediate pre-workout (15 to 60 min)

• 0.3 to 0.5 g/kg
• Sources of faster digestion: banana, dates, maltodextrin
• Useful for morning workouts or when the last meal was more than 4 hours ago

Intra-workout (long sessions >90 min)

• 30 to 60 g/h in liquid
• Dextrose, maltodextrin, sports drink
• In strength training <75 min, rarely necessary

Post-workout

• 1 to 1.5 g/kg distributed over the following 2 to 4 hours
• Accelerates glycogen resynthesis
• Higher priority when there are 2 sessions on the same day or training the next day early

Practical application by profile

Man 80 kg, intermediate, hypertrophy:

• Goal: 5 g/kg = 400 g/day
• Distribution: 80 g coffee, 100 g lunch, 60 g pre-workout, 80 g dinner, 80 g others
• Sources: brown rice, sweet potatoes, oats, fruits, whole grain bread

Woman 65 kg, intermediate, in cut:

• Goal: 3 g/kg = 195 g/day
• Strategy: focus more on pre-workout and post-workout
• Sources: rice, potatoes, fruits, vegetables

Common myths

“Carbohydrates at night make you fat.” No. There is no metabolic difference by time of day when the daily total is controlled.

“Fructose makes you fat.” Natural fructose in fruits is not a problem. Ultra-processed corn syrup in soft drinks is another story, especially in excess.

“Low carb burns more fat.” In the short term there is more fat oxidation, but in equal energy balance, final body composition is equivalent.

“I need dextrose post-workout.” No. Any functional carbohydrate will do. Dextrose is marketing + convenience.

“White rice is worse than brown rice.” In general, brown rice has more fiber and micronutrients; White digests faster and may be better pre- or intra-workout. None are “bad”.

Common mistakes

Extreme low carb + intense training. Performance drops; training volume and quality suffer.

Carbohydrate very close to training in sensitive people. Gastric discomfort; test individually.

Ignore fiber. A diet rich in carbohydrates without fiber generates poor satiety and unstable blood sugar levels.

Only count carbohydrates, ignore calories. Fat and protein also enter the energy balance.

Eat pre-workout industrial sweets. It can give you energy, but the nutritional cost is high; prefer rice, banana, bread.

Tips used by personal trainers

• In students with recurrent fatigue, check carbohydrates before changing anything else in training
• People on low carb who complain about poor performance almost always improve when adding 50 to 100 g/day to pre-workout
• “Refeeds” (high carbohydrate days) in a prolonged cut help performance and psychology
• Banana + oats + coffee: cheap, functional and replicable pre-workout
• For athletes with irregular schedules, prioritize pre-workout and post-workout; rest of the day follow a normal diet

Key Points

• Total daily carbohydrate is more important than type
• 3 to 6 g/kg covers most cases of hypertrophy
• Specific timing plays a role in performance and long training sessions
• Carbohydrates at night don’t make you fat
• Low carb is an option, not an obligation, and it comes at a cost in performance

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Additional reading:

• Protein per day for hypertrophy
• TDEE and energy expenditure
• Fasted training: pros and cons
• Pre-workout: ingredients that work