The Fast Track researchers have just published the results of their pilot study, and they are VERY excited about it! But does this optimism match the actual data? Don’t miss an explosive episode of All Fired Up, as I walk you through this paper step by step, breaking down into plain English what actually happened when 21 teenagers were starved three times a week for 6 months, all in the pursuit of short term weight loss. My guest is the incredible Ruth Leach, whose eating disorder began at the age of 9, when her whole family started fasting for ‘health’. Ruth not only survived her eating disorder, she is now a fierce advocate for everyone at the coal face of this deadly illness. We are LIVID about the lack of information being given to parents and kids who are being introduced to a lifetime of metabolic damage, weight cycling and disordered eating. The Fast Track trial is STILL GOING AHEAD, and we need to keep pushing back against this antiquated, weight biased, dangerous approach to teen ‘health’. Share this one far and wide!!



  • This week we bring you Part 2 of The Fast Track Trial, where we dig into the results of the newly published Fast Track Pilot Study. A pilot study is a mini-version of a larger trial, a practice run for ‘the real thing’, and the results can give you a pretty good idea of what kinds of results we can expect from a larger trial.
  • I really wanted to get a ‘plain English’ summary of what happened in this trial out there.
  • An article in The Age newspaper about the Fast Track controversy stated that:

“While the trial is the first of its kind, Professor Baur said it had come off the back of a successful pilot program in which 25 teenagers followed a similar model and saw benefits in their cholesterol, blood pressure, liver and heart function.”

  • Which is interesting, because Louise was reading the results of the pilot study at the time, and was noticing that in fact the trial results showed no changes in blood pressure, overall cholesterol, or liver function, and only 1 small change out of 9 measures of heart function. This is quite different to what the media was saying!
  • It is so important to go back to the source and have a look at the scientific studies behind the media soundbytes, so you can fact check and see what actually happened.
  • This should be easy, but in reality it’s not. Reading a study is actually quite complicated, and even when you have degrees and training in science, it can still be quite difficult to make sense of what happened. This is why I am here to unpack it for you!
  • It is important for parents and teenagers who may be being targeted to participate in this trial to clearly understand what is likely to happen as a result of taking part. This is why I am doing this podcast.
  • The article has just been published in the Journal of Nutrition, and the title is “Intermittent Energy Restriction is a Feasible, Effective and Acceptable Intervention to Treat Adolescents With Obesity”. What an impressive and optimistic title!
  • But does the optimism match the data?
  • The pilot trial took place at Sydney Children’s Hospital at Westmead, kids were recruited from the adolescent  “O” treatment clinic. 45 kids aged between 12 and 17 were approached, and 30 said yes. There were 25 girls and 5 boys, and the average age of the kids was 15.
  • All of the teens were supposed to have a BMI of 30 or more. In fact, they ranged from a BMI of 27.7 to 52.4, so at least one was well below the weight threshold.**
  • 3 of the kids were from Aboriginal or Torres Strait islander background. 6 of them were born overseas. We don’t know more about the cultural background of the rest of the kids.
  • The experiment ran for 6 months under a dietitian. There were no psychologists or eating disorder specialists involved. For the first 12 weeks all of the kids were placed on Optifast (shakes) and allowed just 600-700 calories a day for 3 days of the week. The rest of the week the kids were told to follow ‘healthy eating guidelines’.
  • After 12 weeks teens were ‘invited’ to either keep starving for 3 days a week, or they could change to starving for 2 or 1 day a week, or they could swap to a ‘continuous prescribed healthy eating plan’ for the next 3 months.
  • 7 of the kids didn’t make it past the 8 week mark. These tended to be ‘heavier’ kids. We don’t know what happened to them after that. 2 more dropped out before the experiment ended, so overall just 21 teens finished the whole 6 months.​
  • The kids were given a Fitbit, but were not given any instructions about physical activity. Mysteriously, the pilot paper never discusses the fitbit results.
  • The primary measure they were looking at was weight loss at 12 weeks, with secondary interest in weight loss at 26 weeks, and they also did a range of health marker measures and one 20 item questionnaire which asked about eating disorder symptoms.
  • 28 of the kids were categorised as ‘insulin resistant’ at the beginning of the study.
  • At 12 weeks, and 26 weeks, the study reports weight change, but it’s actually quite difficult to figure out what that means. This is quite common: weight change in scientific papers can be reported in a huge variety of ways, eg BMI change, z score change, % excess weight loss change.
  • Weight change was primarily reported as ‘percentage point change in BMI 95th%ile’, a very confusing statistic which stops everyday people from figuring out what the actual average change in weight was. A researcher can tell you something is statistically ‘significant’ even if it’s not that meaningful in real life.
  • In the paper, it was reported that at 12 and 26 weeks the kids demonstrated a reduction in the percentage point change in BMI 95th%ile. But what does this actually mean in terms of real life weight change? It is impossible to tell.
  • Luckily, the lead author presented her data at a conference where she did talk about the average kg weight loss for 19 of the 21 study completers.
  • At this conference, she reported that after 12 weeks of intermittent starvation, the kids had lost on average 3.5kg.
  • But by 26 weeks, these changes were not maintained; the teens had regained 1.4kg, so in total after 6 months of regular starvation, they were @2kg less than when they started, and they are likely to keep regaining.
  • That’s not a big change, especially given the huge effort, and we know weight will keep coming back. We know this is the norm for most people who diet: dieting triggers a metabolic defence response, and our bodies fight to regain any weight loss. This is not a failure or a problem, it is the body’s built in response to dieting.
  • What a difference between the raw data at a conference and adding the statistical wizadry in the published paper!
  • There’s more to this story: in the paper,” Figure 3” is a graph which represents each of the kids percentage point BMI95th%ile change at 12 and 26 weeks. There’s a cute little diamond which represents each kid. And when you look at Figure 3, you can clearly see that one kid really stuck out from the rest of them: this kid lost WAY more weight at 12 and 26 weeks than the others, who really didn’t lose much at all. And it seems that this kid – this ‘statistical outlier’ – is responsible for changing the story of this data from concluding that weight loss between 12 and 26 weeks was ‘not maintained’ to saying that it was maintained, all because of one child who may in fact be developing an eating disorder right in front of us.
  • Instead of removing this outlier (which is what a lot of researchers would do, because one person’s unusual results are skewing the data, and this isn’t what science is all about), it was left in. The fact that one person had an unusual response was not discussed in the paper.
  • This is why it’s important to read the studies! To see what actually happened.
  • We can also see in the Figure that at both time points, several of the kids had GAINED weight above the starting point – 3 at week 12 and 5 by 26 weeks. This is normal when we look at it from the perspective of the body’s response to starvation, but weight gain was not discussed in the paper.
  • If you have almost a quarter of your sample over shooting with weight gain, it should be discussed!!
  • Worryingly, the results show a significant reduction in height between 12 and 26 weeks. This was not discussed in the paper. This means that the teens’ growth cycle is being interrupted. If a growing body is not getting adequate nutrition, the body will stop growing in order to compensate.
  • Any impact of starvation on the teens’ menstrual cycle was not investigated. Given that 25 of the 30 were girls, this is staggering.
  • Metabolic impact of starvation on the teenagers’ growing bodies was not measured or discussed in the paper.
  • 28 of the 30 kids were reported to be ‘insulin resistant’ at the outset of the experiment. This was exactly the same after 6 months of semi starvation.
  • Measures of cardiometabolic risk including cholesterol, blood pressure, and insulin resistance did not change after 6 months of intermittent starvation. Small changes in plasma triglycerides were reported, but these were in the normal range to begin with. A small increase in fasting plasma glucose occurred at 6 months, but overall no changes in insulin resistance occurred.
  • Expensive and complicated vascular structure and function (heart) measures were taken, of 9 vascular measures only one was significantly changed by 6 months – arterial wall thickness. Measures of these factors were not taken for all of the completers.
  • The comments made to The Age newspaper regarding the effectiveness of the Fast Track pilot are not true. The teenagers in the pilot study did not see “benefits in their cholesterol, blood pressure, liver and heart function”. At best, one aspect of a secondary marker of heart function improved at 6 months, but the majority of bio-markers were unchanged.
  • Dietary restraint – a measure which can indicate disordered eating and presence of an eating disorder – was significantly increased by 26 weeks. These scores were elevated to start with and became even higher as the starvation diet progressed.
  • The paper does not discuss this at all.
  • Although the paper reported ‘improvements’ in emotional eating and eating for external reasons, these scores were not unusual to begin with, therefore any reductions do not reflect a real life improvement, they are likely just reflecting the fact that the teens were eating less overall.
  • Of 7 measured areas of quality of life, only 2 showed improvement by the end of the 6 months. Interestingly, the results showed that improvements in quality of life were more likely to happen for those kids who did manage to maintain their weight loss at 6 months, the ones who didn’t maintain their weight loss were worse off. Given that we know that all of these kids will continue to regain weight, it seems likely that their quality of life measures will worsen. However, the researchers will not follow them up long enough to find out.
  • So they’ve just reinforced the idea that their self confidence is based on their weight.
  • These outcomes are not great, yet their conclusions are effusive!
  • I am sorry (not sorry) but the conclusions do not match the data.
  • This Pilot study is being used to justify the Fast Track trial, and there is no plain English version out there.
  • My guest Ruth Leach is an eating disorder survivor, her whole family suffered with eating disorder thanks to her dad’s obsession with fasting and his subsequent eating disorder.
  • Ruth is tenacious, she organised a group complaint co-signed by 35 health professionals and people who have experienced eating disorder (many of whom attributed the cause of their disorder to teenage dieting).
  • In the 1960’s Ruth was a ‘fussy eater’ – this would now be labelled as ARFID but back then there was no definition.
  • When Ruth was 9, her dad went on a ‘wacky diet’ to prevent cancer – a fasting diet.
  • The whole family began fasting. Ruth’s sister was 12 when they started fasting, and her growth was impacted – she didn’t grow very tall – Ruth is 8 inches taller than her – and she did not get her period until she was 17.
  • Ruth developed childhood Anorexia, and then developed Bulimia as a teenager. She attributes the fact that she was able to grow taller to the binges she engaged in – they allowed her body the nutrition it craved in order to allow growth.
  • Ruth follows the work of Gwyneth Olwyn, who talks about the concept of ‘extreme hunger’.
  • A lot of people see bingeing as negative, but Ruth’s ‘extreme hunger’ was just her body trying to recalibrate after years of starvation.
  • In Ruth’s early 50’s Ruth’s dad died, from complications of cancer. Even throughout his illness, he kept on fasting – he had an eating disorder. He was hospitalised repeatedly for re-feeding syndrome, and eventually this killed him.
  • At this point Ruth’s eating disorder flared up, and she has been battling Anorexia again.
  • Ruth’s dad did everything ‘right’, but still died of the cancer that fasting was meant to prevent. This is part of the reason the Fast Track study affected Ruth so much.
  • It was only when Ruth’s dad was dying and her symptoms were returning did Ruth realise that it wasn’t just her, but her dad who was eating disordered.
  • Ruth went through years of hell, but is out of her eating disorder now.
  • Ruth became involved in peer support and online eating disorder support networks. Through the process of her recovery, Ruth learned about weight science and the ‘BMI lie” and how the ‘war on obesity’ is a complete beat-up.
  • So much weight bias rampant in the field of ‘obesity’, and also the multi-billion dollar diet and weight loss industry that keeps the beat-up going.
  • One of the reasons the industry is so huge is because our bodies have a built in mechanism to regain weight if we fall below our set point. This theory of set point is well established in science. This ‘war’ against obesity is really a war against biological reality.
  • Ruth is concerned that the Fast Track trial will launch kids into either an eating disorder or a lifetime of disordered eating.
  • The kids will also be introduced to a lifetime of weight cycling, and all of the health issues that come from that. The metabolic impact of repeated dieting causes a lot of the health damage that is attributed to higher weight itself.
  • Ruth’s own life experience, and the experience of everyone in her peer to peer support networks, is that adolescent dieting ‘cost us dearly’.  For some, it has cost their lives: Ruth knows of at least 18 people in the last 2 years who have died from their eating disorder. And as teenagers, many of these people did the same thing that the kids in the Fast Track are being told to do.
  • The Fast Track model is utterly a model of anorexia nervosa being sold to larger kids.
  • Ruth’s complaint to the Fast Track ethics committee went into great detail about weight cycling and the risks to metabolic health, and also the risk of eating disorders. It was a very detailed complaint.
  • We already have so many studies which demonstrate this risk. One study mapped out the pathway to developing an eating disorder. This starts with a child feeling dissatisfied with their body and experiencing bad body image, stigmatisation based on weight, and then dieting. So many of these kids have already crossed 3 out of the 4 stages of development of an eating disorder. So when the head researcher says there is no risk, Ruth asks how can you say that when there is good, consistent science based on thousands of people to say otherwise?
  • The study the Fast Track is based on relies on just 21 kids’ results. And there was no follow up so we have no idea what happens to them a few years down the track.
  • The study talks about the kids being placed on a healthy diet, but also says they were drinking Optifast shakes. On what planet is a shake an example of a healthy diet, especially for growing kids!
  • This is an extreme intervention, but to realise in plain English that this means in all likelihood, your child will lose @3.5kg and then put it back on again, and not see any major health improvements – why on earth would you do this to your impressionable teen?
  • This weight cycling aspect is not something the Fast Track parents or kids are being told about.
  • The Fast Track has also been designed to stop following kids up at one year. At year 2 they have the option of reporting in again, but not a lot of effort is going into seeing what happens longer term. We really need to stop doing these short term studies and to design weight loss trials (if we do them at all) to have a 5 year follow up period – this is the only way we’ll be able to see the patterns of eating disorder development.
  • What will the kids do when they overshoot in weight? Why isn’t anyone following people up?
  • This research is already established – The Minnesotta Semi Starvation experiment showed clearly what happens to a starving body when it re-feeds. We really don’t need to keep ‘proving’ the risks, we need instead to stop exposing people to them.
  • Out of the complaints that were lodged and following meetings with eating disorder organisations like the Butterfly, the Fast Track researchers said they would update the parent consent forms to better inform parents of the risks. That was back in February, and still we’ve heard nothing.
  • In 2019, if you’re going to go into a weight loss experiment, you need to know what the science says about what you can reasonably expect in terms of weight loss and regain, and what to expect in regards to risk. This isn’t rocket science, it’s a basic human right!
  • If they wrote down exactly what to expect, I wonder if anyone would sign their kid up!
  • The increases in restraint are concerning, this is a marker of eating disorder development. Regardless of weight, this is a worry.
  • In Ruth’s networks she advises parents to look at sudden weight losses in their kids, regardless of BMI – look at the disordered relationship with food, not the size of the child’s body.
  • The fast Track researchers are saying that their adjustments to the study protocol – as in, checking more frequently for eating disorder markers – will increase safety, but how on earth can you detect an eating disorder behaviour if the study itself encourages disordered eating and rewarding restriction?
  • If we put together the diary of someone with an eating disorder and a journal of the Fast Track kids, they would look almost identical.
  • If someone was getting really sick, they won’t see it ! They will look like weight loss ‘success’ stories.
  • People with eating disorders feel really good, and positive, when they are restricting. They can feel calm, clear headed, and energetic when they are starving.
  • This is not a normal response to starvation, and it’s a deadly response. The Fast Track researchers will not be able to view this as troubling, and the kid will fall through the cracks.
  • How do you get $1.2 million to fund a study with such unimpressive results? The data do not match the conclusions.
  • Even the title of the pilot study is seriously overblowing their actual findings.
  • We need to listen to the American Academy of Paediatrics – where it specifically says discourage dieting, and skipping meals, and encourage healthy eating. It’s not hard.
  • This experiment is unacceptable. It only makes sense through the lens of weight bias. If we’re worried about people’s health, there’s better ways than risking the metabolic damage that comes from weight cycling from crash diets.
  • At this point the Fast Track trial is still continuing, in spite of the enormous global protest.
  • Please sign the petition!
  • Emerging news this week – the Fast Track researchers have published another paper, a meta-analysis which claims or concludes that hospital based weight loss programs for kids and teens definitely doesn’t cause eating disorders. The team have now told the Butterfly Foundation that they are planning to post this study and the pilot study up on the Fast Track website as a way of communicating risk to the parents and teens who might be enrolling.
  • I will dive into this paper & let you know – is there a difference between the data and the conclusions? Spoiler alert: they’re doing it again…..
  • Informed consent is everything, and this is a serious problem with the researchers slapping up their own research as a way of getting around presenting potential participants with straightforward risk information. This brings up the very issues we’ve talked about today – how on earth are parents supposed to be able to read and understand this dense data?
  • That’s why we need the plain English website where we clearly tell people about the risks and likely outcomes.
  • Visit the Fast Track parents information website!

** Via a letter from a legal firm, the Fast Trackers informed me that this statement is incorrect, and that in fact the kids all had an ‘age and sex adjusted’ adult equivalent of a BMI over 30. No other aspects of my interpretation of the paper (including the interesting tweakery between the presentation figures and the addition of the outlier which changed the results) were challenged by the team.

Resources Mentioned:

Ruth’s complaint

My complaint

The Fast Track parent information website

Gwyneth Olwyn

Sign the Petition

Join our fb group

Connect with Ruth on Twitter

Ruth’s tumbler post

The ‘experts in the room’ blog

What’s wrong with ‘obesity prevention’ ?