Weight Management and Weight Cutting in Kickboxing

Audience

Kickboxing GB coaches, national team staff, selectors, medical and welfare personnel

Purpose

Education, discussion and policy consultation

Status

Consultation draft — not yet an approved KBGB policy

Respond

Online form below or by email to welfare@kickboxinggb.com

1. Why KBGB is consulting coaches

Weight categories are fundamental to fair competition, but the methods used to reach those categories can create avoidable health, performance and safeguarding risks. Practices differ between clubs, disciplines and competition levels, and there is currently no single detailed UK Government standard governing weight making in amateur combat sports.

KBGB therefore wishes to develop an evidence-led national position that is proportionate, enforceable and understood by athletes, parents, coaches, officials and event organisers. Coaches have practical experience of athlete preparation and event delivery, so their views are essential before any policy is approved. This consultation asks coaches to consider:

2. Essential definitions

3. What the scientific evidence tells us

Weight cutting is common, but common does not mean safe

Surveys across combat sports consistently report widespread pre-competition weight manipulation. A major review used by the Western Australian Combat Sports Commission reported that at least 85% of athletes in the combat sports studied used a weight-loss strategy. Typical reported losses are often around 2-5% of body mass, while some athletes report considerably larger reductions.

Acute dehydration can affect health and performance

• reduced blood and plasma volume, increased heart rate and cardiovascular strain;
• impaired temperature regulation and increased risk of heat illness;
• electrolyte disturbance, headache, dizziness, nausea and fainting;
• reduced kidney blood flow and markers consistent with acute kidney injury;
• reduced endurance, repeated-effort capacity and training quality;
• impaired concentration, anticipation, judgement and decision-making;
• irritability, confusion, low mood and reduced self-control.

Some studies find that selected performance measures recover after longer rehydration periods. That does not establish medical safety. Regaining scale weight does not necessarily mean that body-water distribution, plasma volume, electrolytes, cognition and kidney function have fully recovered. In a striking sport, impaired judgement or incomplete rehydration may be particularly significant.

Restriction can lead to REDs and disordered eating

Repeated or prolonged under-fuelling can contribute to low energy availability and REDs in male and female athletes. Possible outcomes include hormonal and menstrual disturbance, impaired bone health, reduced immunity, impaired growth, gastrointestinal problems, sleep and mood disturbance, reduced adaptation to training and increased injury risk. A culture of frequent weighing, body criticism or pressure to retain a category can also contribute to disordered eating.

4. Why children require a different standard

For safeguarding purposes, every athlete under 18 is a child, irrespective of whether competition rules describe the athlete as a child, cadet, junior or youth.

5. What comparable sports and systems are doing

6. Current UK position

There is no single UK Government rule that specifies permissible combat-sport weight loss or sets a universal weight-cutting percentage. General NHS and Government healthy-weight guidance is not designed for pre-competition weight making. This creates a responsibility for sports governing bodies to establish sport-specific safeguards based on foreseeable risk. Relevant obligations and frameworks include:

Pressuring, shaming or punishing a child, or deliberately depriving them of food or fluid to make weight, may become a safeguarding matter rather than merely a poor coaching practice.

7. Proposed principles for discussion

The following are consultation propositions, not approved rules. Coaches are asked to support, reject or amend them and explain how they could operate in practice.

1. Principle 1 — Health before category: An athlete's health and long-term development take precedence over entry, ranking, selection or medal opportunity.
2. Principle 2 — Different standard for children: Under-18s compete at a natural, normally hydrated and adequately fuelled weight. Acute cutting is prohibited.
3. Principle 3 — Adults manage gradually: Adults select a realistic category and make any body-composition change gradually, normally not exceeding around 0.5-1% per week. This is a planning ceiling, not an entitlement.
4. Principle 4 — No artificial dehydration: Deliberate fluid restriction and artificial dehydration methods are prohibited for all KBGB athletes.
5. Principle 5 — Qualified support: Significant, repeated or complex weight management requires appropriately qualified sports nutrition or medical input.
6. Principle 6 — Medical authority: The event medical team may remove an athlete regardless of whether the athlete has made weight.
7. Principle 7 — Coach accountability: Coaches are accountable for practices they direct, encourage, knowingly permit or fail to challenge.
8. Principle 8 — Confidentiality and dignity: Weights and body-composition information are confidential health/performance data. Public weigh-ins, ridicule and negative body comments are unacceptable.

8. Practices proposed for prohibition

Should KBGB prohibit the following in training, squad preparation and competition environments?

• deliberate fluid restriction or intentional dehydration;
• sauna or steam-room weight cutting;
• hot baths used for weight loss;
• impermeable, plastic or rubberised sweat suits;
• training in artificially heated rooms for the purpose of making weight;
• deliberate excessive sweating immediately before weighing;
• vomiting, laxatives, diuretics, diet pills or unapproved weight-loss medication;
• spitting as a weight-making strategy;
• intravenous rehydration except where medically necessary and anti-doping compliant;
• severe fasting or prolonged food restriction;
• punitive exercise for missing weight;
• concealment of weight-making practices from parents, medical staff or KBGB.

9. Possible implementation model

Clubs and coaches

• Discuss category choice well before entry deadlines.
• Use normally hydrated training weight, growth and performance — not appearance — as the starting point.
• Include a parent or carer in every under-18 category decision.
• Do not prescribe weight loss outside professional competence.
• Recognise REDs, disordered-eating and dehydration warning signs.
• Record and report significant welfare concerns through the appropriate pathway.

GB squads and selection

• Record normally hydrated weight at agreed squad checkpoints.
• Agree provisional categories before international entry.
• Do not select a child into a category that requires acute weight loss.
• Permit welfare-led category changes without treating them as misconduct.
• Refer repeated large fluctuations or concerning behaviours to medical/nutrition staff.
• Define what happens where a safe category is unavailable under international entry rules.

Events

• Use calibrated official scales and publish the weighing procedure.
• Provide an opportunity to check the official scales within a controlled period.
• Do not provide or facilitate weight-cutting facilities.
• Make drinking water available.
• Empower medical staff to refuse participation.
• Consider targeted or random secondary weighing and collect anonymised data.
• Define whether an athlete may move category, compete out of ranking, or be withdrawn after missing weight.

10. Consultation questions

Please respond from the perspective of athlete welfare, coaching practice and what KBGB can realistically monitor and enforce. Where you disagree with a proposition, please suggest alternative wording or controls.

1. Should KBGB adopt an explicit rule that under-18s must compete at their natural, normally hydrated and adequately fuelled weight? How should this be defined?
2. Should all deliberate acute weight cutting be prohibited for under-18s, including 16- and 17-year-old international athletes?
3. Should deliberate dehydration also be prohibited for adults, or should KBGB permit limited acute manipulation under professional supervision? If the latter, how could a safe and enforceable limit be established?
4. Is a gradual adult loss guideline of approximately 0.5-1% body mass per week appropriate? Should this be guidance or a mandatory maximum?
5. Which methods in Section 8 (practices proposed for prohibition) should be expressly prohibited? Are any missing or described too broadly?
6. How far in advance should national-team categories be agreed, and how often should normally hydrated weight be recorded?
7. Should KBGB introduce random secondary weigh-ins? If so, when, for which age groups and what consequence should apply?
8. Should an under-18 athlete who grows out of a selected category retain a route to selection in the next category?
9. What should happen at domestic events when an athlete misses weight: category transfer, exhibition status, withdrawal or another approach?
10. What objective signs or thresholds should trigger medical review? Should hydration testing be used, given its practical limitations?
11. What qualifications should be required before someone provides individual weight-management advice?
12. What education should be mandatory for coaches, athletes, parents, selectors and officials?
13. Should a coach-directed breach involving a child be handled under safeguarding, discipline, or both?
14. What records and data could KBGB reasonably collect without creating unnecessary intrusion or body-image pressure?
15. What unintended consequences could arise from the proposed approach, and how could they be mitigated?

11. How to respond by email or post

You can use the online form below, or email your response to the Welfare Officer at welfare@kickboxinggb.com with the subject "Weight Management Consult – [your club name]". Please include:

For each proposal or question, please state:

12. Warning signs requiring intervention

Coaches should stop the weight-making process and seek medical support where an athlete displays:

• confusion, unusual behaviour or poor coordination;
• fainting, near-fainting or persistent dizziness;
• rapid or weak pulse, chest pain or breathing difficulty;
• inability to retain fluid or repeated vomiting;
• severe headache, very dark urine or little/no urine;
• signs of heat illness;
• suspected use of diuretics, laxatives or other prohibited methods;
• rapid repeated weight fluctuation, food anxiety, bingeing or purging;
• menstrual disturbance, recurrent injury, persistent fatigue or other possible REDs indicators.

If you are worried about a child's welfare, report a safeguarding concern. In an emergency call 999.

13. Key evidence and reputable guidance

These sources informed the briefing. They should be read as a body of evidence; no single paper establishes a universally safe acute weight-cutting percentage.

• IOC consensus statement on Relative Energy Deficiency in Sport (2023)
• IOC best-practice recommendations for body composition in sport (2023)
• Effects of rapid weight-loss strategies on physical and cognitive performance (2023) — systematic review
• Effects of rapid weight loss on kidney function in combat-sport athletes (2021) — review
• The current state of weight cutting in combat sports (2019) — narrative review
• British Judo youth weight-management guidance (2025)
• NCAA Weight Management Program
• Western Australian Combat Sports Commission strategy
• UK Anti-Doping: what is banned in sport
• American Academy of Pediatrics: young athlete weight practices

14. Provisional direction for consultation

Coaches are invited to test this position against real-world practice and help KBGB determine the exact policy wording, event procedures, education requirements and enforcement mechanisms needed to make it effective.