A survey on the carnivore diet experience of over 2000 people was carried out in 2020 by a team of researchers from Harvard Medical School and other institutions. The survey findings were recently published on 2 November 2021 in Current Developments in Nutrition.
In this post, we will look at the key findings of the study including who participated in the survey, why they started the carnivore diet, how long they’ve been on the diet, what they ate, and what they experienced after switching to this diet.
If you would like to read the full paper, here is the link.
Who conducted the study?
Authors of the study include:
- Belinda Lennerz, MD, Ph.D. is a researcher and attending physician at the Division of Endocrinology, Boston Children’s Hospital, and Assistant Professor of Pediatrics at Harvard Medical School
- Jacob Mey, Ph.D. is a researcher at Pennington Biomedical Research Center, Lousiana State University
- Owen Henn, MS, RD, LDN is a researcher and dietician at Boston Children’s Hospital
- David Ludwig, MD, Ph.D. is an endocrinologist and researcher at Boston Children’s Hospital, Professor of Pediatrics at Harvard Medical School, and Professor of Nutrition at Harvard School of Public Health.
The study was approved by the Boston Children’s Hospital Institutional Review Board.
Who participated in the study?
Study participants were recruited from carnivore communities on Facebook, Instagram, Reddit, Twitter, and others between 30 March to 24 June 2020.
Of 3,883 respondents, 1,854 were excluded due to age, ineligibility, incomplete information and duplication, leaving 2,029 remaining participants in the study.
Most of the participants were from the US and Canada (64%), Europe (11%), and Australia (8%).
Two third of the participants were male and the remaining were female and other.
The participants’ age was from 18 to 85 and their median age was 44.
Their weight was in the range from 38 kg to 176 kg (84 lb to 388 lb) and their median weight was 76 kg (168 lb).
Nearly two-thirds of the participants (64%) had tertiary education.
Their income status was spread out with 20% reporting high income, 66% middle, and 14% low.
Why did they start the carnivore diet?
93% of the participants stated that the main reason for starting the carnivore diet was health and weight loss.
Within health reasons, their motivations were further broken down as follows:
- 78%: body weight/body composition
- 74%: focus and energy
- 56%: allergy/skin/autoimmunity
- 52%: digestive health
- 46%: athletic performance
- 45%: mental health
- 11%: diabetes.
How long have they been on the carnivore diet?
The survey participants were required to have been on the carnivore diet for at least 6 months.
The participants included in the study reported having been on the carnivore diet from 6 months to 337 months (or 28 years – I wonder who this veteran carnivore is). The median length reported was 14 months.
What did they eat on the carnivore diet?
Ruminant meat (e.g. beef, lamb, goat, and venison) was the most commonly consumed food with 85% reported to have consumed it at each meal or daily.
Eggs were the next popular food for the participants with 44% reported to have consumed eggs at each meal or daily.
Non-dairy milk (e.g. cream and cheese) was also popular with 43% reported to have consumed it at each meal or daily.
Milk was consumed weekly or more frequently by only 17% of the participants and 65% reported having never consumed milk on the carnivore diet.
Pork and poultry were less popular:
- 13% of the participants reported consuming pork at least once a day and 53% had pork one to a few times a week
- 2.5% reported consuming poultry at least once a day and 38% had poultry weekly.
Fish was consumed daily by 3.5% and weekly by 36%.
Organ meat was consumed at least once a week by 42% of the participants.
Bone broth was consumed monthly or more frequently by 52% of the participants.
Condiments were rarely used with only 1.7% reported using at least daily and 53% reported no use.
Herbs and spices were more common and used at least daily by 21% of the participants.
Salt was consumed liberally by 36% of the participants; the rest reported low to medium salt intake or no specific target.
There is a high level of compliance to the diet with:
- 69% never consumed non-starchy vegetables
- 74% never consumed starchy vegetables
- 89% never consumed legumes
- 66% never consumed fruit
- 79% never consumed grains
- 78% never consumed sugar
- 74% never consumed honey
- 65% never consumed non-calorie sweeteners
- 87% never consumed breaded and fried fast food meats
- 81% never consumed candy & milk chocolate
- 75% never ate desserts
- 80% never used multivitamin supplements.
What were their meat choices and preferred doneness?
Their meat choices were as follows:
- 61% chose high fat
- 37% chose moderate fat
- 2% chose lean.
With regard to meat quality:
- 46% chose 100% grass finished or predominantly grass finished
- 54% chose 100% grain finished or predominantly grain finished.
Their preferred doneness was as follows:
- 2% liked raw
- 29% liked rare
- 45% liked medium rare
- 15% liked medium
- 6% liked medium well.
What did they drink on the carnivore diet?
Coffee was a popular drink for this group of carnivore dieters with 57% reported drinking coffee at least daily. However, 24% reported never drinking coffee.
Tea was less popular with only 12% reported drinking tea at least daily and 51% reported never drinking tea.
Alcohol was rarely consumed:
- 83% never consumed beer
- 86% never consumed low-carb beers/seltzers
- 57% never consumed wine. Of the 43% who consumed wine, only 1.1% had it at least daily, 11% had it once to a few times a week, and the rest had it very sparingly
- 55% never consumed spirits. Of the 45% who consume spirits, only 0.5% drank at least daily, 10% had it once to a few times a week, and the rest had it very sparingly.
In other words, if this group had any alcohol at all, their preferences were spirits or wine and most of them only drank very sparingly.
Electrolyte supplements were used at least daily by 17% of the participants while 24% used them from a few times a year to a few times a week, and 59% didn’t use electrolytes at all.
How often did they eat?
Most of the participants (81%) had only 1 to 2 meals a day. In particular:
- 64% ate 2 times a day
- 17% ate 1 time a day
- 17% ate 3 times or more a day
- 2% ate less than once a day.
What did they experience on the carnivore diet?
Overall, the authors of the study found that “contrary to common expectations, adults consuming a carnivore diet experienced few adverse effects and instead reported health benefits and high satisfaction“.
Detailed findings of the study are summarized below.
1. Self-reported changes in health status
An overwhelming majority of the participants experienced positive outcomes. In particular:
- 69% improved chronic disease
- 95% improved overall health
- 91% improved hunger/food cravings
- 85% improved mental clarity
- 66% improved memory
- 83% improved focus
- 69% improved sleep
- 78% improved strength
- 76% improved endurance
- 89% improved energy.
2. Changes in chronic conditions and medication usage
Again, an overwhelming majority of the participants reported improvements in chronic conditions and reduction in medication usage. In particular:
- 93% improved or resolved overweight/obesity (mean BMI decreased from 27.2 to 24.3)
- 93% improved or resolved hypertension
- 84% improved or resolved cardiovascular issues
- 98% improved or resolved diabetes and insulin resistance
- 97% improved or resolved gastrointestinal conditions
- 89% improved or resolved autoimmune conditions
- 96% improved or resolved musculoskeletal issues
- 96% improved or resolved psychiatric symptoms
- 92% improved or resolved urologic issues
- 92% improved or resolved dermatologic issues.
In relation to diabetes medications:
- 90% discontinued or decreased insulin
- 92% discontinued insulin for type 2 diabetes altogether
- 100% discontinued other diabetes injectables
- 84% discontinued oral diabetes medications.
While bearing in mind that these are self-reported results, there is no drug that I know of that has had such spectacular health outcomes as the carnivore diet.
The participants of the survey also reported a high level of satisfaction with the carnivore diet with 98% being either very satisfied or satisfied.
The majority of the participants reported that being on this diet did not impact their social life and that their medical providers and family and friends were mostly neutral or supportive of their dietary choice.
Limitations of the study
As this is based on self-reported data, a potential limitation of this study is recall error and reporting bias.
In addition, as this is an online survey, it is not possible to objectively assess the diet and its health outcomes.
While the findings of this study are probably what the carnivore community would have already known or expected, I think it is significant that a team of researchers from well-respected institutions have actually looked into it.
I think it is a signal that the carnivore diet is becoming a mainstream diet and we can expect a lot more research into this diet in the near future, and, hopefully, many more people will try out and benefit from this way of eating.
I also hope that in the future the carnivore diet will become the first line of recommendation for people who suffer from chronic diseases that are currently labeled as ‘incurable” by medical professionals.
This is exactly what the ICMNI in Hungary is doing at the moment, treating many chronic diseases with a high-fat animal-based diet.
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Please also check out my library of articles on the carnivore diet here which is updated regularly.
Disclaimer: The information in this post is for reference purposes only and not intended to constitute or replace professional medical advice. Please consult a qualified medical professional before making any changes to your diet or lifestyle.