Despite push to be lean, female athletes who eat more perform better, expert says

Jaci VanHeest, PhD, of the University of Connecticut, spoke at the meeting of the International Society of Sports Nutrition in Phoenix last week. In a session called “Down the Rabbit Hole: The Energy and Performance Debate,” VanHeest said there is a difference between “lean and mean” and frankly undernourished, and it’s a boundary that even many trainers and coaches don’t have a good handle on. VanHeest spoke as part of a ‘pre conference’ slate of speakers focusing on the needs and issues of female athletes.

Female biology complicates performance measurements

VanHeest said it has been appreciated for years now that female athletes are more in danger than their male counterparts for running into nutrient deficits because of the biological imperatives of the female anatomy.  Heavy training schedules can mimic environmental stressors of eons past (famine, pestilence, forced relocation marches because of fire and flood, etc.) leading to a ‘decision’ on the part of the body to forgo reproduction because of the poor outlook for survival of the mother and offspring. Black bear females deal with this in a unique way with the delayed implantation of fertilized embryos. In human females, like most other mammals, the response of choice is to suspend ovulation. 

The loss of a regular period forms the first leg of the so-called female athlete triad, VanHeest said.  When athletes exhibited the symptoms, standard practice was to pull them from their training schedules until they recovered.

“​The female athlete triad was first identified in 1992.  Disordered eating, amenorrhea and osteoporosis,​”​ VanHeest said. “​But we now know that this is much more of a spectrum, and that athletes flow in and out of the triad over time.​”​

Body image is a crucial complicating factor in keeping female athletes out of the triad, VanHeest said. Most sports reward female athletes for being lean. Strength sports like weight lifting, shot put, etc., and long distance open water swimming are among the few exceptions. Combine that natural tendency with the hyper critical nature of being in the public eye and having one’s body constantly scrutinized and you have the recipe for disaster, VanHeest said.  Healthy females naturally carry more subcutaneous fat than do men, but social media posts about who’s ‘ripped’ and who isn’t don’t take that into account.

“​It​’​s a hard sell to tell a coach to have their athlete eat more. And it​’​s a hard sell to an athlete, too, to tell them to eat more,​”​Van Heest said.

Study with swimmers

Research VanHeest and her collaborators have been doing could help to better make this case. VanHeest looked at the macroeconomic energy balance, so to speak, over time.  In a test with elite junior female swimmers, her research looked at the totality of the season,  a multi-week process of building training intensity up to a peak and then tapering off just prior to an event.  Performance was measured with repeats in the pool with a ‘rabbit’ setting the pace to mimic race conditions.

“​We wondered, can we just use the hormone levels instead of minute-by-minute logs of what they were eating and what they were doing to tell what​’​s going on with them? In fact we found the hormone markers were telling.​

“​Can you chronically fast, chronically restrict calories, have abnormal hormone levels and still be successful?  What we found was that the ovulation-suppressed group fell off in performance at taper. The women in the cyclic group (those still having regular periods) improved,​” ​VanHeest said.

So the natural tendency for coaches to recommend that their athletes be as light as possible is most likely misguided.  While power to weight ratio and endurance are inescapable facets of many sports, trying just to cut the weight number to improve the outcome of that equation can be self defeating, VanHeest said.  A slightly heavier athlete, one carrying a bit more fat but one who has been eating enough to have normal hormone levels, can outperform a ripped to the bone competitor who is hovering at the fringe of the triad.

Applications to the ‘free living’ state

VanHeest said her interest to study and extrapolate these findings to so-called ‘free living’ athletes, ones who are in active training and may not want to alter those programs to fit in to some study design.  It’s a highly challenging way to gather data, but one that could ultimately be more meaningful, she said.

“​These are people that are out in the world. They are the ones that will mess up your dissertation. Their grandmother gets sick, or they crash their car, and they fall off the program,​”​she said.

Nevertheless, elucidating the biomarkers of when an athlete might be approached the edges of the triad could help cut through the murk, VanHeest said.

“​We were the first to publish a longitudinal study of this sort.  If you are a national caliber athlete, can you link your performance to your energy balance?  Which hormonal systems can indicate that an individual is in a negative energy state?  We have found some ​(thyroid hormones and IGF 1 are some examples), where we can see changes with a negative energy balance and the changes are quite direct,​”​she said.