Question 1

What is nutrition periodization?

Accepted Answer

Nutrition periodization means adjusting your daily carbohydrate, protein, and fat intake based on your training demands. Instead of eating the same thing every day, you match your fuel to the work required. On easy/rest days you eat fewer carbs (3-4 g/kg), on hard training days you eat more (6-8 g/kg), and before a race you carb-load (8-12 g/kg). This maximizes performance while supporting recovery.

Question 2

How many carbs should I eat per hour during exercise?

Accepted Answer

It depends on duration. For sessions under 1 hour, water is usually enough. For 1-2 hours, aim for 30-60g/h of any carb source. For 2-3 hours, increase to 60-90g/h using a glucose:fructose mix (2:1). For ultra-endurance events over 3 hours, recent research shows trained athletes can handle 80-120g/h with a 1:0.8 glucose:fructose ratio, though this requires gut training (Podlogar & Wallis, 2022).

Question 3

What is 'train low, compete high'?

Accepted Answer

'Train low, compete high' is a strategy where you intentionally restrict carbohydrates during some training sessions to enhance metabolic adaptations (like fat oxidation and mitochondrial biogenesis), but fully fuel with carbs before and during competitions for maximum performance. This is typically done during base/aerobic training phases. It should not be used for all sessions — high-intensity work still requires carbs (Impey et al., 2018).

Question 4

What is carb loading and when should I do it?

Accepted Answer

Carb loading (or glycogen supercompensation) means increasing carbohydrate intake to 8-12 g/kg/day for 2-3 days before a race to maximize your muscle glycogen stores. This is most beneficial for endurance events lasting more than 90 minutes. On race morning, consume 1-4 g/kg of carbs 2-4 hours before the start (Burke et al., 2011).

Question 5

Why do I need more protein during off-season?

Accepted Answer

During the off-season, your training volume drops but your body needs to repair and rebuild muscle tissue from the season. Higher protein intake (1.6-2.0 g/kg/day) supports muscle protein synthesis, recovery, and maintenance of lean mass. As training volume increases in the base and build phases, your protein needs decrease slightly because carbohydrates become the priority fuel source (Thomas et al., 2016).

Question 6

What is the glucose:fructose ratio and why does it matter?

Accepted Answer

Your intestine absorbs glucose and fructose through different transporters (SGLT1 for glucose, GLUT5 for fructose). Using just glucose, you max out at ~60g/h absorption. By adding fructose, you engage a second transport pathway, increasing total absorption to 90g/h or more. The traditional ratio is 2:1 (glucose:fructose), but Podlogar & Wallis (2022) suggest a ratio closer to 1:0.8 may be optimal for rates above 90g/h. Sports drinks, gels, and bars with maltodextrin + fructose are designed for this.

Phase	Carbs (g/kg)	Protein (g/kg)	Fat (g/kg)	Key Strategy
Off-Season	3–5	1.6–2	1–1.5	Recovery & repair. Higher protein, moderate carbs, healthy fats.
Base / Aerobic	5–7	1.4–1.6	1–1.2	Build aerobic engine. Moderate carbs support long Zone 2 sessions. Some 'train low' sessions possible.
Build / Intensity	6–8	1.6–1.8	0.8–1	Fuel the intensity. Higher carbs to sustain intervals and threshold work.
Peak / Taper	8–12	1.4–1.6	0.8–1	Carb loading. Maximize glycogen stores 2-3 days before race. Supercompensation protocol.
Race Day	10–12	0.5–1	0.3–0.5	Maximum fuel. High carbs before and during race. Minimize fat and fiber to avoid GI distress.

Exercise Duration	Carbs (g/h)	Carb Type	Why
< 30 min	—	Not needed	No performance benefit from carb intake. Water is enough.
30–75 min	0–30	Any type or mouth rinse	A carbohydrate mouth rinse activates brain reward centers and can boost performance even without ingestion.
1–2 hours	30–60	Glucose, maltodextrin, or sucrose	A single carbohydrate source is sufficient. The SGLT1 intestinal transporter can absorb up to ~60g/h of glucose.
2–3 hours	60–90	Glucose:Fructose mix (2:1 ratio)	Mix glucose and fructose (2:1 ratio) to use both SGLT1 and GLUT5 intestinal transporters, maximizing absorption to ~90g/h.
> 3 hours	80–120	Glucose:Fructose mix (1:0.8 ratio)	Recent research (Podlogar & Wallis, 2022) shows trained athletes can tolerate up to 120g/h with a glucose:fructose ratio closer to 1:0.8. Requires gut training.

Session Type	Carbs (g/kg)	Protein (g/kg)	Fat (g/kg)
Rest Day	2–3	1.6–2	1–1.5
Recovery / Easy (<60 min)	3–4	1.4–1.8	1–1.3
Endurance / Zone 2 (1-2h)	5–7	1.4–1.6	0.8–1.2
Long Session (>2h)	7–10	1.4–1.6	0.8–1
High Intensity (intervals, tempo)	6–8	1.6–1.8	0.8–1
Race / Competition	10–12	0.5–1	0.3–0.5

Nutrition Periodization for Endurance Athletes

Your Profile

Macro Periodization by Training Phase

During-Exercise Fueling Guide (Podlogar & Wallis, 2022)

Daily Macros by Session Type (Micro Periodization)

Frequently Asked Questions