The dangers of under-eating are widely known and acknowledged in health and wellbeing, but could disordered eating or even prolonged under-eating be affecting your boxing performance and your health?
The Female Athlete Triad is a model that has been developed to help diagnose disordered eating within female athletes and the effects this may have. The Triad is made up of three interrelated conditions: energy availability, menstrual function and bone strength. If a female athlete is suffering from one of the three conditions it is more than likely that they could be suffering with the other two conditions as well.
Energy availability is defined as “the dietary energy intake minus exercise energy expenditure”. For example if an athlete consumes 2800 kcal per day and burns 900 kcal per day training and from other exercise leaves 1900 kcal for the remaining essential physiological processes.
Low energy availability in athletes can come about through eating disorders but the majority of cases are through more sport specific circumstances (which may be harder to notice than an eating disorder) e.g. when restricting energy intake too much in an attempt make weight or increasing training volume and intensity without an increase in dietary intake. As athletes have greater exercise energy expenditure than non-athletes the risk of low energy availability is far greater and can have a more profound effect when compared to non-athletes. Energy availability below 30 kcal per kg of fat-free mass reduces reproductive function and bone density. For example, a 60 kg female boxer with 20% body fat (48 kg fat-free mass) would require at least 1440kcal per day remaining after exercise energy expenditure has been taken into account. If this exercise energy expenditure was 900 kcal per day a minimum intake to avoid any negative symptoms would need to be 2340 kcal (1440 kcal + 900 kcal = 2340 kcal).
The normal menstrual cycle can stop due to a reduction in in gonadotrophic hormones which play a role in stimulating oestrogen release from the ovaries. Heavy exercise combined with a low energy intake can reduce oestrogen levels to an extent that the menstrual cycle can be made irregular or even stop.
The reduction in oestrogen that stops the menstrual cycle, in conjunction with a poor diet (specifically low in calcium and a low Vitamin D status) also leads to the weakening of bones through a reduction in bone density (osteopenia), and greatly increases the risk of osteoporosis later in life. This weakening of the bones can lead to increased incidence of fractures, stress fractures and other injuries. This aspect of the triad could have the most severe effect for later in life, as a low bone density at as an adolescent/young adult will likely lead to bone health issues (osteoporosis) later in life. This highlights the importance to avoid bone health issues throughout this development phase.
The good news is that the training boxers complete may help preserve bone mineral density by being mostly compromised of weight-bearing exercise. The frequent running, sparring and gym work places load on the bones which in turn helps strengthen bones and may reduce the impact of a low energy intake and poor diet on bone health.
It has also been shown that food deprivation of 30% increased hunger, whereas and energy expenditure increased by 30% had no effect upon hunger, showing that the body has trouble increasing hunger to encourage eating to match energy expenditure. This 30% increase without a corresponding increase in energy intake would be enough to reduce reproductive function and affect bone health. Furthermore intense exercise can suppress the hunger. Therefore by eating to hunger you may not be in taking the required amount of energy you require, meaning may need to eat more than you think you need to.
Also note, although the symptoms seen are often less severe, low energy availability can also been seen in male athletes and should not be ignored. Bone health and reproductive function can also decrease in male athletes with low energy availability, so it is important that the male athletes out there also pay attention (maybe not to the menstruation part though).
Tips to Help Prevent Low Energy Availability
- During periods of increased training volume or intensity, leading to increased exercise energy expenditure your food intake should increase to mirror the increase expenditure. This will help prevent an unnoticed reduction in low energy availability.
- Avoid “crash dieting” and drastically reducing energy intake when making weight, plan your weight loss around a slower, more gradual weight loss over an extended period of time. Again this will increase energy availability and reduce the risk of factor outlined before.
- Make sure your intake provides you with at least 30 kcal per kg of fat-free mass after your energy used from exercise have been taken into account (a Sport Nutritionist can easily calculate this for you).
- Ensure a good intake of calcium by aiming to consume at least 2 servings of leafy green fibrous vegetables (e.g. broccoli, spinach and kale) plus two servings of low fat dairy per day. If lactose intolerant you may need to increase green veg intake or opt for a calcium supplement to ensure you are consuming enough calcium, however consult a Sport Nutritionist before taking supplements. A good intake of calcium will help maintain bone density and reduce the risk of osteopenia and also osteoporosis later in life.
- Also ensure that you have good exposure to the sun (but not too much that you burn!) as 90% of the Vitamin D we receive is created from the sun’s rays. Instead of running in the dark gym, try to go for a run outdoors in short sleeved t-shirt/vest and shorts. Vit D is required for the absorption of calcium, so a Vit D deficiency may result in reduced bone density even if you are in taking enough calcium. In winter Vit D supplementation may be required as there is very little sun, also the rays that create Vit D do not reach our country between Oct-April, increasing the chances of deficiency. Again, consult a Sport Nutritionist before supplementing.
- Eat to training load and energy intake and not to hunger. Exercise may suppress hunger and increased exercise energy expenditure may not lead to increased hunger. Meaning you may not feel hungry but are desperately requiring more calories. If you are full but know that you need more energy, try smoothies and shakes as an easier way of getting your energy in.
However the greatest piece of advice would be if you experience any of the above “Female Athlete Triad” symptoms then consult your doctor or a sports nutritionist as soon as possible. Some of these side effects may be irreversible so taking action sooner rather than later is vital.