REFERENCES
REFERENCES & RESOURCES
Evidence. Education. Better Questions.
At Against the Grain Health, information is meant to help you become more organized, informed, and prepared when discussing your health with your healthcare providers.
Health information is constantly evolving. Whenever possible, educational content on this website is supported by peer-reviewed research, government health agencies, medical organizations, and other established scientific resources.
Personal experiences shared on this website are identified as personal experiences and should not be interpreted as proof that the same approach will produce the same results for another person.
Fasting, Metabolic Health & Autophagy
Effects of Intermittent Fasting on Health, Aging, and Disease
de Cabo R, Mattson MP.
Effects of Intermittent Fasting on Health, Aging, and Disease.
New England Journal of Medicine. 2019;381:2541–2551.
DOI: 10.1056/NEJMra1905136
This major review discusses intermittent fasting, metabolic switching between glucose and ketones, cellular responses to fasting, and the current evidence surrounding potential health effects of intermittent fasting.
View the study — New England Journal of Medicine
Fasting, Calorie Restriction & Autophagy
Bagherniya M, Butler AE, Barreto GE, Sahebkar A.
The effect of fasting or calorie restriction on autophagy induction: A review of the literature.
Ageing Research Reviews. 2018;47:183–197.
DOI: 10.1016/j.arr.2018.08.004
Autophagy is a cellular housekeeping and recycling process. This review examines research concerning fasting, calorie restriction and activation of autophagy pathways.
Carnivore & Very-Low-Carbohydrate Nutrition
Carnivore Diet Research
Lennerz BS, Mey JT, Henn OH, Ludwig DS.
Behavioral Characteristics and Self-Reported Health Status among 2029 Adults Consuming a “Carnivore Diet.”
Current Developments in Nutrition. 2021;5(12):nzab133.
DOI: 10.1093/cdn/nzab133
This study surveyed 2,029 adults who reported following a carnivore diet for at least six months. Participants reported dietary practices, health status, satisfaction, medical conditions and laboratory information.
Important limitation: This was a self-selected, self-reported observational survey. It does not establish that the carnivore diet caused the reported outcomes, and the long-term health effects of this dietary pattern remain insufficiently studied. Published scientific commentary has also addressed limitations of the self-reported data.
View the carnivore study — PubMed
View published discussion of study limitations — PubMed
Blood Glucose, A1C & Metabolic Tracking
Understanding A1C
The National Institute of Diabetes and Digestive and Kidney Diseases explains that the A1C test provides information about average blood-glucose levels over approximately the previous three months and is used in diagnosing and managing diabetes and prediabetes.
A1C and blood-glucose testing do not always tell exactly the same story, and certain medical circumstances can affect A1C results.
NIDDK — The A1C Test & Diabetes
Home Blood-Glucose Monitoring
Home glucose meters can provide useful information for monitoring blood glucose, but they are not perfect. Proper technique, test-strip condition, environmental factors and other variables can influence readings.
The FDA provides guidance on obtaining more reliable measurements and understanding the limitations of home glucose meters.
FDA — Getting the Most Out of Your Blood Glucose Meter
Understanding Laboratory Results
Laboratory results are valuable pieces of health information, but an individual number does not provide a complete picture of someone’s health.
Results need to be considered alongside symptoms, medical history, physical examination, medications, other testing and other clinical information.
Reference ranges can also differ among laboratories because laboratories may use different methods and reference populations. When following trends over time, consistency in testing methods and laboratory location may be useful.
MedlinePlus — How to Understand Your Lab Results
Blood Pressure & Home Tracking
The American Heart Association recommends home blood-pressure monitoring for people with high blood pressure and explains that keeping a record of measurements over time can provide healthcare professionals with more useful information than a single measurement.
Correct cuff size, positioning, adequate rest before measurement and proper technique are important for obtaining accurate readings. Home monitoring does not replace regular medical care.
American Heart Association — Home Blood Pressure Monitoring
Digestive Health & Symptom Tracking
Digestive symptoms can have many potential causes, and persistent or chronic symptoms may require evaluation using medical history, physical examination, blood tests, stool testing, breath testing, endoscopy or other diagnostic approaches depending on the circumstances.
Keeping organized records of symptoms, food intake, medications and changes over time can make it easier to provide a healthcare professional with a more complete history.
Probiotics, Supplements & Nutrition Products
Dietary supplements can contain vitamins, minerals, herbs, botanicals, probiotics and other ingredients. Evidence, effectiveness and safety vary considerably among individual products and ingredients.
For probiotics specifically, benefits depend on factors including the particular microorganisms or strains involved; simply having a higher number of colony-forming units does not necessarily mean a product provides greater health benefits.
NIH Office of Dietary Supplements — Supplement Fact Sheets
NIH Office of Dietary Supplements — Probiotics
Medication Information
When medications are discussed on Against the Grain Health, those discussions are educational and are not recommendations to start, stop or change a prescription.
The U.S. Food and Drug Administration maintains resources for FDA-approved medications, including prescribing information, Medication Guides, reported side effects and drug labeling.
FDA — Find Information About a Drug
Why Tracking Matters
A single measurement is often only one piece of information.
Blood pressure, blood glucose, symptoms, medications, food reactions, sleep, laboratory results and other health information can change over time. Keeping organized records can make patterns easier to recognize and can provide healthcare professionals with more complete information during appointments.
Against the Grain Health planners, trackers and educational resources are designed around this principle: organize the information you already have so you can ask better questions and have more productive conversations with your healthcare providers.
About the Research
Scientific research changes as new evidence becomes available.
Some topics discussed on Against the Grain Health have extensive clinical evidence behind them, while others including highly restrictive dietary approaches such as the carnivore diet currently have much more limited evidence.
Where evidence is preliminary, observational, self-reported, conflicting or incomplete, it should be treated accordingly.
Against the Grain Health does not believe personal experience should be presented as scientific proof, nor should a single study be treated as the final answer to a complex health question.
Medical Disclaimer
The information provided by Against the Grain Health, PORVA, its website, articles, blogs, newsletters, planners, trackers, downloads and educational materials is provided for educational and informational purposes only.
Nothing on this website is intended to diagnose, treat, cure or prevent any disease or medical condition, and the information provided is not a substitute for individualized medical advice, diagnosis or treatment from a qualified healthcare professional.
Do not start, stop or change medications, supplements, treatment plans or medical care based solely on information presented on this website.
Always discuss medical symptoms, laboratory results, medications, dietary changes and treatment decisions with an appropriate licensed healthcare professional.
If you believe you are experiencing a medical emergency, seek immediate medical care.
BOOKS & HEALTH RESOURCES
Books That Have Informed My Health Research
Over the years, I have spent countless hours reading, listening, researching, and comparing different perspectives on nutrition, metabolic health, digestive health, autoimmune conditions, respiratory care, fasting, insulin resistance, and chronic disease.
The books below are among the resources that have contributed to that ongoing education. Inclusion on this list does not mean that Against the Grain Health endorses every statement or recommendation made by an author. These resources are provided so readers can explore different perspectives, review the information for themselves, and continue asking informed questions.
Respiratory Care
Egan’s Fundamentals of Respiratory Care
A comprehensive professional respiratory-care reference covering respiratory anatomy and physiology, assessment, diagnostics, respiratory disease, mechanical ventilation, oxygen therapy, airway management, and respiratory treatment.
Metabolic Health, Insulin Resistance & Nutrition
Why We Get Sick — Benjamin Bikman, PhD
Explores insulin resistance and its relationship to metabolic health and chronic disease.
Metabolical — Robert H. Lustig, MD
Examines metabolic health, processed foods, insulin, chronic disease, and the differences between treating symptoms and addressing underlying metabolic dysfunction.
Fat Chance — Robert H. Lustig, MD
Explores obesity, metabolic dysfunction, insulin, sugar, processed foods, and the biological mechanisms that influence hunger, weight, and health.
Lies I Taught in Medical School — Robert Lufkin, MD
Examines changing scientific perspectives surrounding metabolism, nutrition, chronic disease, and conventional approaches to several common health conditions.
Grain Brain — David Perlmutter, MD
Explores the relationship between nutrition, carbohydrates, metabolic health, inflammation, and brain health.
Toxic Superfoods — Sally K. Norton, MPH
Examines dietary oxalates, potential sources of high oxalate exposure, and the author’s perspective on how oxalates may affect susceptible individuals.
Low-Carbohydrate & Carnivore Nutrition
Lies My Doctor Told Me — Ken D. Berry, MD
Challenges a number of commonly repeated health and nutrition recommendations and encourages patients to investigate the evidence behind medical advice.
Common Sense Labs — Ken D. Berry, MD
Discusses laboratory testing and ways patients can become better informed about the health information contained in their lab results.
Stay Off My Operating Table — Philip Ovadia, MD
Discusses metabolic health from the perspective of a cardiothoracic surgeon and focuses on metabolic dysfunction and cardiovascular risk.
Fasting & Metabolic Disease
The Obesity Code — Jason Fung, MD
Explores obesity through a hormonal and metabolic framework, with particular emphasis on insulin and dietary patterns.
The Diabetes Code — Jason Fung, MD
Discusses type 2 diabetes, insulin resistance, nutrition, and fasting from a metabolic perspective.
Gut Health & the Gut-Brain Connection
Gut and Psychology Syndrome — Natasha Campbell-McBride, MD
Discusses the author’s GAPS framework and proposed relationships among intestinal health, nutrition, the microbiome, and neurological and psychological health.
Gut and Physiology Syndrome — Natasha Campbell-McBride, MD
Expands the GAPS framework to include digestive, immune, metabolic, inflammatory, and other physiological conditions.
Put Your Heart in Your Mouth — Natasha Campbell-McBride, MD
Discusses nutrition, cardiovascular health, cholesterol, dietary fats, and the author’s perspective on heart disease.
Vegetarianism Explained: Making an Informed Decision — Natasha Campbell-McBride, MD
Examines vegetarian and plant-based dietary patterns from the author’s nutritional and physiological perspective.
Autoimmune Health & Nutrition
The Paleo Approach — Sarah Ballantyne, PhD
Explores autoimmune disease, immune function, intestinal health, nutrition, lifestyle factors, and the Autoimmune Protocol (AIP).
PHYSICIANS, RESEARCHERS & HEALTH EDUCATORS
Books are only one part of my continuing education. I have also spent many hours listening to lectures, interviews, podcasts, presentations, and educational videos from physicians, researchers, clinicians, and people with extensive personal experience.
Dr. Ken Berry
Family physician, author and health educator whose educational content frequently addresses metabolic health, laboratory testing, low-carbohydrate nutrition, ketogenic diets and carnivore nutrition.
Dr. Robert Cywes — The Carb Addiction Doc
Physician and metabolic-health educator whose work focuses on carbohydrate addiction, obesity, insulin resistance, metabolic health, behavior and nutrition.
Dr. Anthony Chaffee
Physician and health educator known for discussing carnivore nutrition, human nutrition, metabolic health and the potential effects of eliminating certain foods.
Kelly Hogan — Zero Carb Life
Long-term zero-carb/carnivore educator who shares her personal experience, interviews, educational discussions and experiences from the carnivore community.
Benjamin Bikman, PhD
Metabolic scientist and researcher whose work focuses extensively on insulin, insulin resistance, metabolic health and the biological regulation of energy metabolism.
Robert H. Lustig, MD
Pediatric neuroendocrinologist, researcher and author whose work discusses sugar, fructose, insulin, processed foods, obesity and metabolic disease.
Jason Fung, MD
Physician and author known for educational work involving fasting, insulin resistance, obesity, type 2 diabetes and metabolic health.
Philip Ovadia, MD
Cardiothoracic surgeon and author whose educational work emphasizes metabolic health and its relationship to cardiovascular disease.
Sally K. Norton, MPH
Nutrition researcher, educator and author whose work focuses on dietary oxalates and their potential effects in susceptible individuals.
Dr. Natasha Campbell-McBride
Physician, author and creator of the GAPS nutritional protocol whose books and educational work focus on nutrition, digestive health, the microbiome and proposed gut-body and gut-brain relationships.
David Perlmutter, MD
Neurologist and author whose work explores nutrition, metabolism, inflammation, the microbiome and brain health.
Dr. Robert Lufkin
Physician, author and educator whose work focuses on metabolic health, chronic disease, nutrition and changing perspectives within medicine.
A NOTE ABOUT THESE RESOURCES
The inclusion of a book, author, physician, researcher, educator, podcast, video or other resource on this page does not mean that every claim made by that source has been scientifically established or is endorsed by Against the Grain Health.
Some of these resources represent established medical knowledge, while others discuss emerging research, clinical observations, hypotheses, personal experiences or approaches that remain debated within medicine and nutrition science.
I believe there is value in examining different perspectives, comparing them with available evidence, tracking your own health information, and discussing questions and concerns with qualified healthcare professionals.
Education should lead to better questions—not replace medical care.
Last reviewed: August 2026
Against the Grain Health
PORVA Path of Resurgent Vitality & Autonomy