The Man Who Ate 6,000 Calories a Day and Defied the Scale
A deep dive into Billy Craig and how he became "Hypermetabolic"
Our story today begins somewhere close to where we left off last week in looking at human metabolisms that have been significantly suppressed and what we might do about it.
Having a significantly suppressed or efficient metabolism, to me, holds the key to why some easily lose weight on a diet vs many that don’t. Why some get hypervitaminosis or some toxicity vs not. And why, despite society telling them they are lying, many suffering with weight issues cannot seem to lose weight whilst white knuckling through a 1000kcal/day diet.
After last week’s post and in looking at where my own metabolism should be vs where it actually is I started to dig into the questions:
What can one do about it?
How do we carry out metabolic repair?
Can you increase your metabolism?
Amongst the science and research which might hold the answer to these questions the little known story of Billy Craig and his 6000kcal/day diet came up.
Billy hasn’t made it easy to piece together his story.
One minor podcast appearance, a self published book with a single 3 star review (which I finished this morning), a sporadically updated patreon, a few forum mentions and a site with several 404 links is most of what is available on the story.
I read through it all.
His original diet experiment ran from 2004 - 2006, and his self published book was released 12 years later in 2018 which definitely added to the complexity of the collage I’ve tried to put together here.
In this post I’ll go through the best explanation of his story, some fascinating insights from his book and how I think it all fits in the context of the current metabolic crisis we all face.
I’ve reached out to Billy and hope to get him on the Patchwork podcast soon!
The 6000kcal Diet Experiment
Background and Context
Billy Craig is an independent researcher with a Masters in Psychology whose work focuses on the psychology of dieting behaviors and the metabolic effects of energy intake.
His research challenges traditional dieting culture, which often emphasizes calorie restriction and increased physical activity.
Instead, Craig advocates for consistent eating patterns, suggesting that the body performs better with stable, reliable energy supply. This philosophy is detailed in his science heavy book, Consistent Eating: Is Dieting Harming Your Health And Your Weight Loss?, where he explores how restrictive diets can lead to compensatory behaviors and metabolic slowdowns.
Billy's interest in high calorie intake stems from his belief that the thyroid gland, which regulates metabolism, functions optimally with consistent energy availability.
This led him to conduct a personal experiment on the back of a disagreement to test whether increasing calorie intake could enhance metabolic function, potentially leading to weight loss without restriction.
Before being deep in independent research Billy was an professional mountain biker and then a personal trainer which is where this all began.
Sometime around the end of 2003/ beginning of 2004 it appears that Billy had a disagreement with a trainer in his gym as to the advice they were giving clients in order to get them to lose weight.
He’d heard “Eat less, move more” one too many times it seems. Taking your total energy expenditure, subtracting 500kcal from it and expecting to lose 1lb of fat a week (3500kcal) from energy restriction seemed not only banal but simply unsuccessful both in the short term and long term.
And so from what I can piece together, Billy set to prove his gym wrong by trying to increase his metabolic rate through adaptation (not moving more) such that a high metabolic rate would naturally erode adipose tissue given it’s demand for consistent energy.
Methodology and Timeline
From 2004 to 2006, Billy conducted a self-experiment where he gradually increased his daily calorie intake. The experiment progressed as follows:
Initial Intake: Started at 3500 calories per day, ignoring advice to reduce by 500 calories, based on his understanding of thyroid function and metabolic regulation.
Structure of Intake: In trying to keep energy stable, Billy apportioned his food intake equally across all of the hours of the day to the smallest breaks possible. No forced fasting, no big meals. Similar amount of food every few hours.
Progression: He increased linearly to 4500 calories until weight stable, then increased linearly again until ultimately reached 6000 calories per day.
Duration: The experiment spanned approximately two years, with measurements taken at various stages.
Exercise Levels: Remained consistent, as Craig was teaching spin classes and competing in sports, providing a stable physical activity baseline.
The experiment aimed to test the hypothesis that consistent high calorie intake could increase metabolic rate, allowing the body to burn more calories and potentially reduce fat stores without the need for calorie restriction.
To achieve the high calorie intake, particularly at 6000 calories, Billy ended up relying on candy for ease of counting, carrying, and palatability which is an important detail for understanding the practical implementation and somewhat defies what we know about PUFAs and their role in metabolic suppression both at the tissue level and in the thyroid.
Observed Outcomes and Physiological Changes
During the experiment, Billy observed several physiological changes, which are detailed in his blog post, Kellogg Passion Killer and 6000 kcal per day.
These include:
Increased Body Temperature: His body temperature rose, which is often associated with an elevated metabolic rate, suggesting his body was adapting to burn more energy.
No Fatigue: Despite the high calorie intake, he reported no fatigue, indicating efficient energy utilization and possibly improved metabolic efficiency.
Dramatic Fat Loss: Unexpectedly, his fat levels decreased significantly, even though he was consuming a large calorie “surplus”. This aligns with his premise that the body can adapt to burn excess calories when consistently provided with energy.
Metabolic Adaptation: His resting metabolic rate (RMR) increased to match the intake, as measured by his boss during the experiment. This supports the idea that the thyroid and metabolic systems can adjust to higher energy demands when consistently fueled.
These outcomes suggest that, for Billy, the high and consistent calorie intake led to a hypermetabolic state, in which he had made his thyroid more active.
As explored in his book - a hypermetabolic state is a luxury of abundance where your metabolism is fundamentally inefficient. You have enough energy to do any and all metabolic processes and then you just rid yourself of the excess through heat. Something we consistently see in newborns.
Challenges and Limitations
While the experiment yielded interesting results, it also highlighted several challenges:
Dependency on Constant Feeding: At 6000 calories, Billy struggled to go without food for more than an hour, indicating a high dependency on constant energy supply. The hypermetabolic state whilst slow to build to, was like a runaway train.
This is detailed in his Patreon Q&A, What Would Billy Say? June 2018 Q&A, where he mentioned structured meal times, including having to wake up in the middle of the night to eat, to maintain the intake.Use of Junk Foods: To meet the calorie goals, especially at such high levels, he relied on junk food (candy). This is a practical consideration but raises concerns about nutritional quality, as these foods lack essential nutrients, are full of life destroying Omega-6 fats and could pose long-term health risks.
Although this does lend clues to how seed oils become more dangerous when we have slower metabolisms, and how high metabolisms can protect against them.Discomfort at High Intake: A discussion on the Low Toxin Forum notes that Billy mentioned the experiment becoming uncomfortable, with him unable to sit still at the end.
We categorically know that in a metabolically suppressed state, Non-Exercise Activity Thermogenesis (NEAT) is drastically ramped down so it would make sense in a hypermetabolic state, the alternative would happen. You become that high energy kid that can’t sit still.
Even as an adult I know people like this.
Billy noted that being at either end of the metabolic spectrum (very low or very high calorie intake) comes with health risks. He concluded that for him, the ideal range was between 3200 and 3600 calories per day, back where he started and in his podcast appearance stated that, that is where he like to stay now.
Broader Implications and Controversy
Billy's experiment fundamentally challenges dieting wisdom that is taught to doctors, nutritionists, dietitians, PhDs and personal trainers, particularly the "eat less, move more" mantra.
His findings suggest that, consistent eating at higher calorie levels can lead to metabolic improvements and fat loss, contrary to the expectation that high calorie intake always leads to weight gain.
This is an unexpected detail, as most people associate high calories with weight gain, not loss.
Although if you are dogmatic enough to believe that metabolisms don’t down regulate, I can imagine thinking that they can up-regulate would cook your brain.
I did find some controversy around the applicability and safety of such high calorie diets.
Another chat on the former Ray Peat forum, highlighted that while Billy is seen as knowledgeable and credible, his experiment is considered extreme.
Some argued it is not suitable for beginners or the general population, with concerns about the health risks of such high metabolic rates and the reliance on candy.
I found all this research hilarious.
So many peaters complain of weight gain in trying up up-regulate their metabolisms and I think no one considers their own context when attempting this.
If you start at 3500kcal TDEE, moving to 3750kcal is a 7% increase.
But if you’re coming from 2000kcal TDEE and moving to just 2250kcal you are making a 12% jump! You also are starting from a much less productive place which would suggest your increases need to be a smaller % than when the train is already going.
Billy's work also touches on the psychological aspects of dieting, as seen in his book, which discusses how restrictive diets can lead to feelings of failure and compensatory behaviors.
Recap
Experiment Period
2004-2006
Calorie Levels Tested
3500 calories, 4500 calories, 6000 calories
Final Calorie Intake
6000 kcal per day at 10st (weight)
Exercise Levels
Remained roughly the same (teaching spin classes, competing as usual)
Observations
Body temperature increased, no fatigue, fat levels fell dramatically, metabolism rose to match intake, suspected hyperactive thyroid, struggled without food for longer than an hour
Health Risks Noted
Being at either end of the metabolic spectrum comes with health risks, ideal range for the individual was 3200-3600 kcal
Food Source
By the end of the experiment he required junk food (candy) for ease of counting and carrying
Consistent Eating (Billy’s Book)
I picked up Billy’s book in an attempt to fill in some of the gaps in my understanding of this story and with hope that he, maybe, had broken down what he did into a protocol someone else could follow.
He does not lay out a protocol. Instead his book, which again was published 12 years after his original experiment ended, makes a detailed, scientific and enthralling case that:
Repeated calorie restriction can put a human in a state of Torpor (metabolic hibernation) which previously I had only thought could happen from eating Omega-6 fats.
A suppressed or efficient metabolism is correlated with early aging, and people who live well past the median lifespan have high metabolisms
One of the ways your body becomes “more efficient” is to shrink your kidneys, digestive tract and other organs whilst sparing your brain and heart (your liver actually gets bigger as the need for gluconeogenesis in starvation is greater)
High protein diets increase calorie restriction without realizing it and may be suppressing your metabolism
3 meals a day plus snacks is a result of social conditioning and not conducive to an optimal metabolism.
The book refers to a second book that will come, although, with 6 years since publishing, there is no sign of a second book.
How does it fit in?
Well to be quite honest with you. Billy’s story and his book were a breath of fresh air (besides the fact that the entire book is in italics which is rather annoying).
Everywhere we look, read, hear is the message eat less, do it harder.
Just this year famed bodybuilding coach Lyle McDonald who popularized protein sparing modified fasts recommended taking thyroid hormones and GLP-1s when approaching his extreme dieting approach to the dismay of many followers who have attempted his “Rapid Fatloss” protocols and failed.
What he managed to do, and the case he put forward is one that many in this space have discussed. It feels right, but modern science has basically ignored it.
I find it partially terrifying to think people are regularly shrinking their organs through fasting and restriction. Repairing that metabolic damage will likely take years.
A high metabolism makes sense as the ultimate longevity hack too. At a higher metabolism you can detox faster, hypervitaminosis is less probable. You have more energy to spare for heat and immunity and repair and brain function.
Eating consistently to force your feedback systems to learn that you are in an energy abundance makes sense too. I keep imagining a flywheel in my head. You want to keep it running. Just give it a little push over and over.
People with low metabolisms and low thyroid complain of constipation. Maybe having a slowed metabolism and then eating 33-50% of your entire food load in one go is a recipe for disaster? It takes energy to digest a huge bolus of food. I would bet smaller consistent mini meals would rapidly speed up digestion.
In fact, I actually think this might be what is critically missing in the pro-metabolic diet space. The honey diet seems a LOT more reasonable if you are microdosing honey in the feeding window rather than trying to replace your normal meal volumes with honey.
Conclusion
The last three weeks posts took a lot of 6am and 8pm reading and writing time, but have seemingly, like always in my life, come at the perfect time.
I now fully understand what I have done to myself, where my metabolism and thyroid is at and where I want to be. I hope you do to.
Based on Billy’s work I have made some changes in my life to be reported on soon and we’re incorporating broad stroke metabolic screeners and opinions in our work at Patchwork.
I hope this post leaves you enlightened and empowered. Happy Saturday everybody.
p.s. If you came here via substack, you might like more more frequent postings on X.
p.p.s Thanks for answering the poll last week! We made some awesome changes at patchwork and are soon incorporating OATs to see how your energy generation system is broken (see below)
Want help?
Feeling crappy and struggling to navigate all the diet tribes? Just want to feel great again? We help people find the optimal diet to shed weight without calorie counting based on your DNA - come check it out at Patchwork.
We promise there’s no cardio or calorie counting required.
It seems to me that one major problem with many dietary intervention then is the drastic changes in carolie intake, especially when people inevitably fall off the wagon due to cravings and extreme hunger. A very slow and deliberate approach with reverse dieting up to a reasonable amount of energy is then to be preferred, but it will probably take a lot of time to fix metabolism. Makes GLP-1 even more enticing, especially for people who never experienced a metabolism working at optimum.
I'm also wondering what would have happened if Billy wasn't physically active. At some point fidgeting probably isn't enough.
I used to eat constantly and massively every day, and I did this for years. In the end I was very very fat and very sick. So I would say there is a context where this applies, a context I do not fit in.