How to time carbohydrate, protein, and fluid intake before, during, and after competition; the loading protocols that maximize glycogen stores; sizing up energy needs and body composition goals; and catching the early warning signs of RED-S and disordered eating.
What actually shows up on the exam
The goal of the precompetition meal is simple to state and easy to get wrong in practice: top off liver and muscle glycogen, keep the athlete adequately hydrated, and do both without anything sitting heavy in the stomach once the whistle blows. The variable that decides what's safe to eat is time remaining before start — the closer to competition, the smaller and simpler the meal needs to be, because digestion competes with working muscle for blood flow and a full stomach is a liability once intensity climbs.
Three qualities describe a good precompetition meal regardless of sport: it's carbohydrate-forward (the primary fuel being topped off), low in fat and fiber (both slow gastric emptying), and built from familiar foods the athlete has already tolerated well in training — competition day is the wrong time to test something new.
| Time before start | What to take in | Why |
|---|---|---|
| 3–4 hours | A full meal, roughly 1–4 g/kg carbohydrate plus moderate protein, low fat and fiber | Long enough for the stomach to clear before competing |
| 2–3 hours | Fluid, ~5–7 mL/kg body mass | Front-loads hydration with time to void any excess |
| 1–2 hours | A small carbohydrate-rich snack, ~1 g/kg, plus fluid | Tops off glycogen without adding meaningful digestive load |
| 10–20 minutes | 200–300 mL fluid; carbohydrate only if well-tolerated in training | Last practical window to correct hydration status |
Where people lose points
A concentrated sugar bolus taken alone in the last 30–60 minutes before starting can trigger a rebound drop in blood glucose once exercise begins, because insulin is still elevated when the working muscle's own glucose uptake kicks in. That risk is athlete-specific — some tolerate it fine — which is exactly why the rule is to rehearse the precompetition routine in training, never to improvise it on competition day.
Carbohydrate loading is a short-term manipulation of training and diet designed to push muscle glycogen stores above their normal resting level — glycogen supercompensation — for events that are continuous, at moderate-to-high intensity, and last roughly 90 minutes or longer. Below that duration, normal glycogen stores are already sufficient and loading buys little.
| Protocol | Structure | Length |
|---|---|---|
| Classic (depletion) protocol | An exhaustive glycogen-depleting workout, followed by several days of low carbohydrate intake alongside continued hard training, then a switch to a very high-carbohydrate diet (roughly 8–10 g/kg/day) while training tapers sharply | ~6 days |
| Modified (taper) protocol | No depletion phase — training volume simply tapers down over about a week while carbohydrate intake climbs, reaching roughly 8–12 g/kg/day for the final 1–3 days before competition | ~6 days |
Why most athletes and coaches prefer the modified version
The classic depletion phase works, but the low-carbohydrate days leave athletes fatigued, irritable, and more injury-prone right before an important event — a real cost for a technique that's supposed to help performance. The modified protocol reaches a similar glycogen supercompensation without ever forcing the athlete through that depleted, glycogen-starved window.
For anything under about an hour, water is usually enough — glycogen stores aren't the limiting factor yet. Past that mark, feeding strategy shifts to defending blood glucose and sparing glycogen, and the target carbohydrate intake climbs with event duration.
| Property | Target range | Why it's tuned there |
|---|---|---|
| Carbohydrate concentration | 6–8% | Balances fuel delivery against gastric emptying — go much higher and emptying slows, pulling fluid the other direction |
| Sodium | ~20–30 mEq/L (roughly 450–700 mg/L) | Helps drive fluid absorption in the gut and offsets sweat sodium losses |
| Osmolality | ~280–330 mOsm/kg (isotonic) | Close to blood plasma's own osmolality, which keeps gastric emptying and intestinal fluid uptake fast |
The first few hours after finishing are when the body is most primed to resynthesize glycogen and repair tissue — muscle is more insulin-sensitive and glucose transport into the cell runs faster than at rest. Two nutrients matter most in that window: carbohydrate, to refill glycogen, and protein, to kick off repair and remodeling.
| Window | Target |
|---|---|
| Within ~30–60 minutes of finishing | ~0.25–0.3 g/kg high-quality protein (roughly 20–25 g for most athletes) |
| Spread across the following 24 hours | Divided doses every 3–4 hours, totaling ~1.2–2.0 g/kg/day depending on training goal |
| Carbohydrate, first several hours post-exercise | ~1.0–1.2 g/kg/hour to maximize the rate of glycogen resynthesis |
Applied — same-day double sessions
The 1.0–1.2 g/kg/hour carbohydrate target matters most when an athlete has to be ready to perform again within about 8 hours — a same-day double, a multi-event meet, a tournament bracket. With a full 24 hours to recover, total daily carbohydrate intake matters more than hitting that hourly rate precisely.
Total daily energy expenditure (TDEE) is built from three separate pieces, and knowing their relative size explains why exercise alone is rarely the whole story in either a surplus or a deficit.
| Component | Share of TDEE | What it reflects |
|---|---|---|
| Resting/basal metabolic rate (RMR/BMR) | ~60–75% | Energy needed to keep basic life-sustaining functions running at rest — the largest piece for almost everyone |
| Thermic effect of food (TEF) | ~10% | Energy spent digesting, absorbing, and metabolizing what was just eaten |
| Activity energy expenditure (AEE) | ~15–30% (higher in athletes) | Planned exercise plus everyday incidental movement (NEAT) |
Estimating total energy need starts from a resting-metabolic-rate equation, then multiplies by a physical activity level (PAL) factor that accounts for how active the person is outside of rest.
| Category | Approx. coefficient | Description |
|---|---|---|
| Sedentary | ~1.2 | Little to no structured exercise |
| Lightly active | ~1.375 | Light exercise roughly 1–3 days/week |
| Moderately active | ~1.55 | Moderate exercise roughly 3–5 days/week |
| Very active | ~1.725 | Hard exercise roughly 6–7 days/week |
| Extremely active | ~1.9 | Very hard daily training plus a physically demanding job or two-a-days |
| Category | BMI (kg/m²) |
|---|---|
| Underweight | <18.5 |
| Normal weight | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obese (classes I–III) | ≥30.0 |
A common mix-up
BMI is a population-level screening tool, not a body-composition measurement — it can't distinguish lean mass from fat mass. A muscular, low-body-fat athlete can land in the "overweight" BMI category despite having excellent body composition, which is exactly why BMI alone is a poor fit for classifying athletes.
Both directions of change respond best to small, sustained energy imbalances layered on top of appropriate training — large, fast swings tend to cost performance, recovery, or lean mass.
On the gain side, the surplus has to be paired with a progressive resistance training stimulus — extra calories without a training driver mostly add fat, not muscle. On the loss side, keeping protein intake relatively high (generally above typical sedentary recommendations) and continuing resistance training both help preserve lean mass while the deficit does its work. Deficits that run much larger than roughly 500–750 kcal/day, sustained for long stretches, raise the risk of losing performance capacity, strength, and — as covered next — energy availability low enough to cause systemic problems.
RED-S describes impaired physiological function — across nearly any body system — caused by inadequate energy availability: the energy left over for the body to run on after subtracting what exercise burned off, relative to fat-free mass. It's a broader, more accurate successor to the older term female athlete triad, which only described three linked problems (low energy availability, menstrual dysfunction, low bone density) in female athletes specifically. RED-S recognizes the same root cause — energy availability that's too low, whether intentional or not — can affect male and female athletes alike, and that the consequences reach well beyond reproductive and bone health.
Energy availability, the number underneath RED-S
Energy availability = (energy intake − exercise energy expenditure) ÷ fat-free mass. An optimal value sits around 45 kcal/kg fat-free mass/day; energy availability dropping below roughly 30 kcal/kg fat-free mass/day is the widely cited threshold where the body starts down-regulating function to cope with the shortfall. Low availability can happen with disordered eating — but just as easily from an athlete simply under-eating relative to a heavy training load without ever intending to restrict.
Because energy availability touches nearly every regulatory system, the consequences of RED-S span far more ground than the old triad implied:
Why this matters for a strength and conditioning professional
RED-S often shows up first as a performance problem, not an obvious health one — a plateau, unexplained fatigue, recurring minor injuries, or a string of illnesses in an athlete who's training hard and "should" be improving. Recognizing that pattern and referring out to a physician or sports dietitian is squarely within scope; diagnosing or treating it is not.
Clinical eating disorders are diagnosed by qualified medical and mental health professionals, not by a coach — the value for a strength and conditioning professional is knowing the general behavioral and physical patterns worth flagging early, well before things reach a diagnostic threshold.
| Pattern | General signs to notice |
|---|---|
| Anorexia nervosa | Severe, sustained food restriction; intense fear of weight gain; distorted perception of body size; body weight significantly below what's expected |
| Bulimia nervosa | Recurring episodes of binge eating followed by compensatory behavior — self-induced vomiting, laxative misuse, or excessive exercise; body weight often appears normal, which is exactly why it's easy to miss |
| Disordered eating (subclinical) | Chronic dieting, rigid food rules, guilt or anxiety around eating, exercising specifically to "earn" food or "burn off" a meal — doesn't meet full diagnostic criteria but carries real physical and performance risk and can progress toward a diagnosable disorder |
A trap in this section
Athletes with disordered eating patterns don't reliably look underweight — sport, especially anything with a weight class, aesthetic component, or leanness advantage, can mask warning signs behind a physique that looks "fit." Behavioral signals (rigid rules, secrecy around eating, exercising to compensate for food) are often more reliable red flags than appearance alone.
An athlete wants to eat a full precompetition meal. How far before the event should that meal be finished?
C. A full meal needs roughly 3–4 hours to clear the stomach. Closer windows are reserved for progressively smaller carbohydrate snacks and, in the final 10–20 minutes, fluid alone.
Which best describes the modified carbohydrate loading protocol compared to the classic protocol?
B. The modified protocol reaches glycogen supercompensation through a training taper and climbing carbohydrate intake, without ever forcing the athlete through a depleted, low-carbohydrate phase.
A sport drink is formulated at roughly 6–8% carbohydrate concentration primarily to optimize what?
B. That concentration range balances carbohydrate delivery against gastric emptying rate — concentrations much higher slow emptying and can work against hydration.
For an event lasting close to 3 hours, which carbohydrate intake target is most appropriate?
C. Events past about an hour benefit from 30–60 g/hr of carbohydrate; very long events can push higher using combined carbohydrate sources (such as glucose plus fructose) to raise the absorption ceiling.
Roughly how much protein should an athlete target within 30–60 minutes after finishing a hard training session?
A. Roughly 0.25–0.3 g/kg (about 20–25 g for most athletes) shortly after finishing supports the repair process; total daily protein intake matters more once that immediate window has passed.
Which component of total daily energy expenditure is typically the largest for most people, including trained athletes?
C. RMR/BMR typically accounts for roughly 60–75% of TDEE, even in athletes with a substantial training load.
A client has a BMI of 27.5 kg/m². Which classification does that fall into?
C. Overweight spans 25.0–29.9 kg/m². Note that BMI can't separate lean mass from fat mass, so it's a weak tool for classifying muscular athletes specifically.
What is the primary underlying cause of RED-S?
B. RED-S is driven by inadequate energy availability — energy intake minus exercise energy expenditure, relative to fat-free mass — whether that shortfall is intentional or not.
How does RED-S differ from the older "female athlete triad" concept?
B. The triad described three linked problems in female athletes. RED-S traces the same root cause — low energy availability — across a wider range of systems and across male and female athletes alike.
Which observation is the strongest early warning sign of disordered eating in an athlete who appears to be at a normal body weight?
B. Appearance is an unreliable indicator — many athletes with disordered eating patterns, including bulimia nervosa, maintain a normal-looking body weight. Behavioral signs like rigid rules and compensatory exercise are more reliable red flags.
This chapter is original study material covering topics also addressed in Essentials of Strength Training and Conditioning, 5th edition (NSCA/Human Kinetics). It is an independent work, not a reproduction or paraphrase of that text. This guide is not affiliated with, endorsed by, or sponsored by the National Strength and Conditioning Association (NSCA). CSCS® and Certified Strength and Conditioning Specialist® are registered trademarks of the NSCA.