A Risky Strategy: The Truth About Rapid Weight Loss for Athletes ⚠️

We've all been there: staring down a big race, maybe a little heavier than we'd like to be. The idea of dropping a couple of kilos for a better power-to-weight ratio is a tempting one, but it’s often seen as a no-go zone due to the risks of low energy availability (LEA). LEA is essentially when you're not eating enough to fuel your training and your body's basic functions.

Chronic exposure can lead to some serious health and performance issues, but what about a quick fix? A recent study with elite race walkers explored just that: what happens when you intentionally go into a short period of severe energy restriction?

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The researchers wanted to see if they could get the benefits of a lower body mass without compromising performance or health. They put a group of elite race walkers on an intensified training block and split them into two groups. One group maintained a high energy diet, while the other group went into severe energy restriction for nine days. The key here is that both groups completed a 10,000-meter race at the start and end of the trial, with a standardized pre-race fueling strategy.

Changes in body mass over the duration of an endurance training camp in highly trained race walkers (n = 23) who were divided in two groups to consume a diet providing high energy/CHO availability (HCHO) for a 6-d baseline phase before being assigned to 9 d adaptation phase of either HCHO (n = 12) (A) or LEA diet (n = 11) (B). Data for the change relative to initial body mass (∆BM) for the two groups matched across study activities (2C). Data are presented as mean ± SD. Points sharing a letter are not different from one another (P > 0.05). ***Main effect of time (P < 0.001).

The results were interesting, if a little surprising. The low-energy group dropped an average of 2.0 kg, with a significant portion of that being fat mass. Their performance improved by about 3.5%, while the high-energy group improved by 4.5%. So, while the low-energy group did lose more weight, their performance gains weren't quite as good as the group that was fully fuelled. What’s more, the athletes on the low-energy diet reported increased stress and reduced recovery compared to the high-energy group. Over half of elite athletes in various sports have been found to have energy availability below the recommended threshold, highlighting how common this issue is.

Mean data and individual responses for absolute (A) and relative (B) V̇O_2peak obtained during the incremental max test performed before baseline phase or after adaptation to an HCHO (n = 12) or an LEA (n = 10) diet in highly trained race walkers. Absolute (C) and relative (D) oxygen uptake and calculated substrate oxidation rates (E, CHO; F, fat) during the four-stage economy test. Data are presented as mean ± SD. Significant differences: P < 0.01; *P < 0.001.

WEIGHT LOSS: The Takeaway for You

So, what does this mean for us? While the study suggests that a short, strategic period of severe energy restriction can work, it's not without its costs. It's a high-risk, high-reward strategy that should be used sparingly and with a lot of thought. My general advice is to avoid LEA whenever possible to prevent negative health and performance outcomes. However, if you're an experienced cyclist looking to make a targeted, short-term change, here's a protocol based on the study's findings:

1. Limit the Restriction: Keep this period of low energy availability to no more than seven to nine days. This isn't a long-term plan; it's a targeted intervention.

   
   

2. Prioritise Recovery: Recognise that you're going to feel more stressed and less recovered. If possible, lighten your training load or allow for additional recovery time to compensate for the added stress.

   
   

3. Refuel for Race Day: The study's participants had a standardised carbohydrate loading protocol before their final race, which is likely a key reason their performance didn't tank. Make sure you return to a high-carbohydrate, high-energy diet in the 24 hours leading up to your event to refuel your muscles and liver.

Mean and individual data for performance of 10,000-m race walking event (A) and change in race performance (B) in highly trained race walkers at baseline and after adaptation to an HCHO (n = 12) or an LEA (n = 9) diet. Changes in BM on race day (C) and correlation between change in prerace body mass and 10,000-m race performance (D). Significant differences ***P < 0.001.

This isn't an excuse to go on a crash diet. It's a reminder that every action has a reaction, and a brief, strategic period of restriction must be followed by proper fuelling to work.