Beyond calories and cardio: 4 science-backed truths about athletic fueling, recovery, and performance

Fitness enthusiasts and dedicated athletes are constantly hunting for an extra edge: better tracking, specialized supplements, or tighter calorie control. Yet a more demanding plan is not always a better one. Sometimes persistent fatigue, poor recovery, and declining performance reflect inadequate fueling rather than a lack of discipline.

Sports nutrition research challenges several familiar assumptions. An everyday pantry ingredient has a role in performance research, under-fueling is not limited to women, and neither scale weight nor a single blood test tells the whole story.

1. Baking soda has performance evidence, but it is not a harmless shortcut

Sodium bicarbonate, the compound in baking soda, is a buffering agent. It raises bicarbonate outside muscle cells, helping buffer the hydrogen ions associated with intense exercise. The International Society of Sports Nutrition's 2021 position stand reports benefits for some high-intensity activities, particularly efforts lasting roughly 30 seconds to 12 minutes.

The research includes cycling, running, swimming, rowing, muscular endurance, and some combat sports. That does not mean every athlete, workout, or endurance event benefits equally. Individual responses differ, and gastrointestinal symptoms can cancel out any performance advantage.

For context, studies often use a single dose around 0.2 to 0.3 grams per kilogram of body weight, taken 60 to 180 minutes before exercise. These are research protocols, not instructions to try a household remedy. Higher single doses tend to increase side effects without consistently improving performance further.

Bloating, nausea, vomiting, and abdominal pain are recognized risks. Sodium load and possible interactions also matter, especially with kidney or heart conditions, high blood pressure, or sodium restrictions. Discuss use with a qualified sports health professional rather than experimenting before an event. Multi-day protocols may reduce competition-day symptoms for some people, but they do not eliminate risk.

The position stand also notes that expectation and placebo effects may contribute to performance changes. A supplement cannot substitute for adequate food, appropriate training, sleep, and recovery.

2. Under-fueling affects men as well as women

Relative Energy Deficiency in Sport, usually shortened to REDs, describes a syndrome of impaired health and performance associated with problematic low energy availability. In practical terms, too little dietary intake remains to support the body's normal functions after exercise demands are accounted for.

The International Olympic Committee expanded the earlier female-athlete framework to recognize broader effects and athletes of any sex. In men, persistent under-fueling may be associated with lower testosterone, reduced libido, and changes in reproductive function. In women, menstrual changes can be an important warning sign. Neither sex is protected simply by looking lean, strong, or competitive.

Other possible consequences include:

• Bone health: reduced bone density and greater vulnerability to bone stress injuries.
• Metabolism and recovery: reduced resting expenditure and difficulty recovering from training.
• Immune function: more frequent illness and impaired repair.
• Performance and well-being: declining training responses, fatigue, and psychological strain.

A 2024 review reported an average detected prevalence of low energy availability of 39.5% across the four included studies that measured it. This is a finding from a small, selected research sample, not a population-wide estimate and not proof that nearly 40% of all athletes have REDs.

3. BMI and food logs cannot tell the whole fueling story

Body mass index is a weight-to-height measure, not a direct measure of fat, muscle, or adequate nutrition. A muscular athlete can have a higher BMI without excess body fat. An athlete with a BMI in the usual reference range can still be under-fueled.

The IOC framework treats body measurements as context within a broader evaluation, not a standalone diagnosis. Overemphasizing weight or body composition can also create unnecessary pressure, particularly for adolescents. Health, training capacity, and age-appropriate development should come first.

Food logs can help identify patterns, but estimates of food portions and exercise expenditure are imperfect. People may unintentionally omit snacks, misjudge quantities, or rely on inaccurate device readings. A log is a conversation starter, not a definitive test for REDs.

Body composition measures, training history, symptoms, eating patterns, and professional judgment need to be considered together. Repeated fatigue or injury deserves attention even if the scale looks reassuring.

4. Seventy-nine research markers do not equal a home diagnostic checklist

The 2024 review identified 79 markers across 13 studies. That variety illustrates how researchers measure different aspects of under-fueling, and why consistent methods matter. It does not establish 79 independently validated diagnostic tests.

Bone density, body measurements, the thyroid hormone triiodothyronine (T3), and resting metabolic rate appeared frequently. The table describes how often measures were used in those studies, not how accurate they are at diagnosing an individual.

Measure	Use in the 13 reviewed studies	Interpretation
Bone mineral density	76.9%	Bone health context, often measured using DEXA
T3 concentration	76.9%	A hormone finding that needs professional interpretation
Body measurements	76.9%	Weight, BMI, and fat mass do not diagnose under-fueling alone
Resting metabolic rate	69.2%	Results depend on testing conditions and prediction methods

Low T3 or a lower-than-predicted resting metabolic rate may accompany prolonged under-fueling, but neither is specific to REDs. Other conditions can produce similar findings. A normal thyroid result also does not rule out a fueling problem.

Do not interpret published thresholds as instructions to order or diagnose yourself from a single test. The IOC approach combines screening, risk indicators, and a physician-led evaluation, ideally supported by a wider sports health team.

The practical takeaway: fuel the training you are actually doing

Better athletic performance is not simply the result of eating less and pushing harder. Match food intake to training demands, allow recovery, and notice changes in function rather than relying only on body size.

Persistent exhaustion, recurring bone injuries, menstrual changes, reduced libido, or unexplained performance decline are reasons to seek qualified care. The question is not just whether your plan makes you lighter, but whether it supports a healthy, resilient athlete.

Important reader note

This article is for general education, not personalized advice, diagnosis, or treatment. Research findings describe study populations and do not guarantee individual outcomes. Speak with a qualified health professional before changing prescriptions, taking supplements, or starting strenuous exercise, especially if you have a health condition.