Is getting too lean risking your fertility?
Bump up your baby chances with the report every fit woman should read
AS F-WORDS GO, ‘FAT’ AND ‘FERTILITY’ CAN MAKE THE MOST OPINIONATED OF US CLAM UP. BUT EVIDENCE IS GROWING THAT STRIVING TO CUT TOO MUCH OF THE FORMER CAN REALLY SCREW WITH HOW YOUR BODY NATURALLY TAKES CARE OF THE LATTER. WH INVESTIGATES HOW TO GET THE BALANCE RIGHT
While muscle-bound, sweat-drenched Instagram stories (and discussions over brunch plates practically bursting with protein) seem to confirm that the strong-not-skinny message is alive and well, outside the wellness bubble, the statistics show a different story. In the most recent
WH Global Naked Survey, a staggering 90 per cent of readers surveyed said they wanted to reduce their levels of body fat, while Roy Morgan Research shows 72 per cent of Aussie women aged 18–24 want to lose weight even though only 36 per cent have a BMI in the overweight category. What this points to? A desire to get really lean. But as this body goal remains hugely popular, what isn’t immediately clear is the damage super-low-fat goals will make to your future gains – and it’s all down to a simple yet little-known concept called ‘energy availability’.
We’re talking about fertility specifically, and that monthly reminder that everything in the ovary arena is working. Instagram sensations Sally O’neil (@thefitfoodieblog) and Sarah Stevenson (@sarahs_day) have spoken about previously losing their periods in the face of overtraining and under-eating, with O’neil acknowledging her abs-quest wasn’t worth the health sacrifice. Francesca Baker, 30, took up running at uni to counterbalance boozy nights but wound up hooked on daily gym sessions and restrictive diets. “I stopped taking the pill around the same time, so I told myself the abrupt stop in my periods was down to that, instead of what was becoming an out-ofcontrol desire to be ‘healthy’.”
It wasn’t healthy. Francesca was suffering from relative energy deficiency in sports (RED-S, pronounced ‘reds’). “RED-S is a disparity between food intake
(the energy you’re consuming) and the nutrition required to cover the energy demands of basic housekeeping tasks in the body and exercise,” says sports endocrinologist Dr Nicky Keay. Like having a smartphone on 9 per cent battery, fail to top up its juice and it reverts to an energy-saving mode where automatic functions – in women’s case, periods – switch off.
Unsurprisingly, humans aren’t quite as homogeneous as iphone models, so the level at which these processes slow or halt is different for everyone. A regimen or body fat percentage that one woman can keep up without saying goodbye to regular periods could affect the reproductive cycle of another.
“When you’re focused on lowering body fat, whether through an extreme exercise regimen and/ or restricting kilojoules, the body perceives you to be in a stressed state and decides this is not the time to reproduce,” says Dr Meggie Smith, reproductive endocrinology expert at the University of Southern California. “Signals from the brain to the ovaries, known as the hypothalamic-pituitary-ovarian axis, shut down. The luteinising hormone [which triggers ovulation] isn’t produced and the ovary neither releases an egg or makes oestrogen and progesterone.”
While being overweight or obese disrupts your reproductive system by producing too much oestrogen, veer towards the other extreme and “you essentially enter a postmenopausal state”, warns Smith.
Given that RED-S could severely disrupt your fertility, it’s fair to wonder why this hasn’t been grabbing headlines. Until recently, the phenomenon was known as the female athlete triad – or simply ‘the triad’ (we can’t imagine why the acronym FAT didn’t take off). The triad linked energy deficiency to menstrual disturbances and loss of bone mineral density to explain once-puzzling period loss data, such as why 69 per cent of female university-aged dancers* and 65 per cent of female long-distance runners* didn’t have regular cycles. But in 2014, the International Olympic Committee renamed it, realising that the triad wasn’t actually a threesome after all.
Energy deficiency was also found to slow metabolic rate, impair immunity, increase fatigue and affect cardiovascular and even gut health. Plus, in July last year, the British Journal Of Sports
Medicine published research that explored RED-S in undernourished
male athletes, while Keay believes the pressing issue for women is decoding its effect on non-athletes – you know, the rest of us.
“Elite athletes have the expertise of a coach or team doctor. A dedicated amateur with no such support is therefore more at risk of RED-S if they’re taking measures to significantly decrease body fat through exercise and dieting,” she explains. “I see this in dancers: aspiring students are often at risk until they join a company, where there is a support network.”
Keay’s interest isn’t just professional, though. As a child gymnast, she’d train four times a week, alongside ballet classes that left her incredibly lean. As a result, it wasn’t until after her second son was born – conceived with the help of an ovulation-inducing tablet and injection – that she got her first period. She was 32. “I was fortunate to work in a hospital where I could seek conception advice. If I hadn’t
had this medical knowledge, who knows what would have happened. That’s why it’s important women are aware of RED-S.”
“In my experience, those most susceptible to falling into difficulty are women in their 20s,” says registered dietitian and sports nutritionist Laura Clark. “They hit the gym six or seven times a week – sometimes twice a day. Intense training is one thing, but if the nutrition isn’t there to support that energy expenditure and body function, body fat drops significantly and you will run into real difficulties.”
On the dilemma of too much exercise versus too little food, Smith says that kilojoule restriction is far more dangerous than highintensity exercise. The study
Neuroendocrinology of Nutritional
Infertility found that just one month of a significant drop in energy intake could mess with menstrual function.
But as long as you have a BMI in the healthy range, you’re golden, right? Well, the experts can’t seem to agree on how useful traditional measurements are. The late biologist Rose Frisch found that evaluating weight alone could be misleading – as muscles are heavy (80 per cent water compared to 5–10 per cent water in fatty tissue), many athletes appeared in the “normal” weight range despite having no periods. Even with body composition scales, Clark points out that you’ll get different results depending on where you are during your menstrual cycle, as that affects how much water your cells hold.
Frisch suggested women needed at least 17 per cent body fat to fall pregnant – nicknaming it “sex fat”, as it provides energy for reproduction. This is in line with Royal College of Nursing findings in 2015, stating the healthy body fat percentage for women aged 20–39 is between 21 and 33 per cent.
It’s why energy availability – the difference between energy intake and expenditure from exercise – is the new buzzword. “The energy requirement is 188kj per kilogram of lean body mass for endocrine function,” says Keay. “It’s also about the quality of your diet. I had a dancer who got to that level by eating biscuits and sweets, but she still had no periods as she wasn’t covering the major food groups.”
How to spot whether you’re at risk of RED-S? “Even if your weight is steady, if your periods have stopped or become irregular and you’re not on a contraceptive method, don’t ignore it,” urges Keay. “Your doctor will exclude other causes first, like polycystic ovary syndrome and thyroid disorder, then look at your nutrition in line with your training.”
Experts also highlight other signs that your quest to become lean is going too far, even before your periods show any changes. Personal trainer Luke Worthington recommends being alert to physiological changes such as hair loss (a sign of inadequate nutrition), increased body hair (a layer of soft downy hair) and a pot belly caused by intestinal gas. Psychological warning signs are just as important. “If you find yourself obsessing over a missed workout, scheduling your entire life around exercise or meal prep and losing interest in sex, take them as cues that you may be too focused on getting leaner in an unhealthy way,” he adds.
Loss of periods through too little body fat is reversible. Your fertility is informed by a host of factors, from your age to stress levels. Dooley says if you’re not underweight and not losing weight via restriction, you’re likely to conceive unless other medical conditions are at play. He studies the possibility that unreleased eggs aren’t lost for good due to RED-S, but are stored, freezer-like, inside your body.
Getting normal menstrual function back is, in fact, more food science than rocket science. The International Olympic Committee’s report on RED-S found that the only strategy that has received scientific scrutiny – and worked – was to add an energy-rich supplement (in the study, it was a daily liquid meal product of around 1255–2510kj) and a weekly rest day. The general advice when you’re exercising hard is to think about what you can add to your diet, rather than what you can take away.