How Different Diets Impact Your Health | Dr. Christopher Gardner
Dr. Christopher Gardner, professor of medicine and director of nutrition studies at Stanford, discusses dietary controversies, comparing various diets. He emphasizes eliminating processed foods, the importance of fiber and low-sugar fermented foods for gut health, and protein needs.
Deep Dive Analysis
14 Topic Outline
Individual Dietary Needs and Resilience to Various Diets
Lactose Intolerance and Raw Milk Research
Wheat and Gluten Intolerance in the US Diet
Understanding Processed Foods, Additives, and Regulations
Food Industry Funding and Investigator Bias in Nutrition Research
Comparing Low-Carb, Low-Fat, Keto, and Mediterranean Diets
The Concept of a Whole Food, Plant-Based Diet
Transforming the American Diet: Taste, Health, and Environment
Scalability and Challenges in Food Production Systems
Revisiting Protein Requirements and Storage
Plant Proteins: Completeness and Bioavailability
Evolution of Plant-Based Meat Alternatives
Vegan vs. Omnivore Twin Study Results and Communication Challenges
Microbiome, Inflammation, Fiber, and Fermented Foods
9 Key Concepts
Lactose Intolerance
A condition where individuals stop producing the enzyme lactase after weaning, making them unable to break down lactose in dairy products. The majority of the world's population is lactose intolerant, with Northern Europeans being a notable exception who developed the ability to continue producing lactase into adulthood.
NOVA Classification
A system developed by Carlos Montero from Brazil to categorize foods based on their degree of processing, independent of their nutritional content. It highlights the potential impact of cosmetic additives (dyes, flavorants, gelling agents) on health, suggesting they have an additive effect beyond traditional nutritional concerns.
GRAS (Generally Recognized As Safe)
A designation by the FDA for food ingredients that are considered safe by qualified experts, allowing them to be added to foods without pre-market approval. This list has expanded significantly over decades, enabling the food industry to incorporate numerous ingredients without extensive human safety testing.
Equipoise in Research
A principle in scientific study design where researchers aim to create fair comparisons between different interventions. In nutrition studies, this means designing competing diets (e.g., low-carb vs. low-fat) to be of the highest possible quality and healthfulness, rather than making one intentionally 'crappy' to ensure a desired outcome.
Whole Food, Plant-Based Diet
A dietary approach that emphasizes consuming mostly plants, which can include varying amounts of animal products (e.g., 10-30%). This term is distinct from 'vegan' and 'vegetarian' and focuses on a diet rich in unprocessed plant foods, aligning with Michael Pollan's 'eat food, not too much, mostly plants' philosophy.
Protein Flip
A concept introduced by the Culinary Institute of America that reorients meal composition. Instead of a large piece of meat as the central focus, the 'protein flip' places vegetables, grains, and beans at the center of the plate, with meat serving as a smaller side dish or condiment, emphasizing taste and culinary appeal.
Nitrogen Balance Studies
A historical method used to determine protein requirements by measuring the amount of nitrogen (a key component of protein) consumed in food versus the amount excreted from the body. Participants were kept in controlled environments for months, with protein intake adjusted until intake matched output, establishing a baseline requirement.
Telomere Caps
Protective caps at the ends of chromosomes that naturally shorten with age. Longer telomere caps are generally associated with biological youth and better health outcomes, and some studies suggest dietary interventions can influence their length.
Epigenetic Clocks
Biological markers that estimate an individual's biological age based on patterns of DNA methylation, which are changes in gene expression without altering the underlying DNA sequence. These clocks can indicate whether someone's biological age is older or younger than their chronological age.
10 Questions Answered
No, there isn't one best diet. Humans are incredibly resilient and can thrive on vastly different diets, as evidenced by various indigenous populations. The common factor in unhealthy diets globally is the prevalence of processed, packaged foods.
A study conducted by Dr. Gardner found that raw milk did not alleviate symptoms of lactose intolerance, with participants experiencing the same GI distress as with conventional pasteurized milk.
While not all cases are clinically diagnosed celiac disease, the high prevalence of wheat intolerance in the U.S. may be due to Americans consuming an immense amount of refined wheat, which often comes from a very limited variety of wheat strains, unlike the more diverse grain consumption in other parts of the world.
While industry funding can introduce subtle influences, researchers can mitigate bias by registering trials, pre-defining primary outcomes, allowing third-party data analysis, and making data publicly available. A larger concern can be investigator bias, where studies are designed to favor a particular diet by making it 'kick-ass' while a comparison diet is made 'crappy'.
The DIETFITS study, involving 600 people over a year, found no average difference in weight loss between healthy low-carb and healthy low-fat diets. Neither genetic predisposition nor insulin resistance predicted individual success on either diet, suggesting that both approaches can be effective if implemented healthfully.
No, this is a myth. All plants contain all 20 amino acids, including the nine essential ones. While the proportions of certain amino acids (like lysine in grains or methionine in beans) might be lower than in animal proteins, consuming a variety of plant foods easily provides all necessary amino acids.
In a study comparing Beyond Meat to high-quality red meat, Beyond Meat showed cardiometabolic benefits, including lower LDL cholesterol, TMAO, and weight. While initially criticized for a long ingredient list and high sodium, these products have been reformulated, and the sodium content often becomes comparable to salted red meat when consumed.
The 8-week study found that the vegan twins experienced lower LDL cholesterol, lower fasting insulin, increased microbial diversity, and statistically significant improvements in epigenetic clocks (suggesting biological youth) and telomere length compared to their omnivorous twins.
A study showed that consuming six servings of low-sugar fermented foods daily for six weeks significantly increased microbial diversity in the gut and decreased 20 different inflammatory markers. This benefit was observed regardless of baseline microbial diversity.
In a study, increased fiber intake did not, on average, increase microbial diversity or decrease inflammatory markers. Individuals with low baseline microbial diversity sometimes had an adverse, inflammatory reaction to a sudden increase in fiber, suggesting that fiber benefits might be more nuanced and personalized.
18 Actionable Insights
1. Consume Fermented Foods Daily
Incorporate fermented foods like plain yogurt, kefir, kombucha, kimchi, and sauerkraut into your daily diet to significantly increase gut microbial diversity and reduce inflammatory markers in your body.
2. Fiber Intake: Assess Gut Diversity First
If your baseline gut microbial diversity is low, prioritize increasing fermented food intake before drastically increasing fiber, as a ‘fire hose of fiber’ might lead to adverse inflammatory responses.
3. Aim For Three Fermented Food Servings
Strive to consume at least three servings of low-sugar fermented foods daily, as study participants maintained this intake and experienced sustained benefits even after the formal study period.
4. Adopt The “Protein Flip” Meal Structure
Implement the ‘protein flip’ by making vegetables, grains, and beans the main focus of your plate, with meat serving as a smaller accompaniment (e.g., two ounces) rather than the central component.
5. Eat Less, Better Quality Meat
Aim for ’less meat, better meat’ by reducing overall consumption and choosing high-quality, sustainably sourced options, which can offer health benefits and potentially balance your food budget.
6. Avoid Standard American Diet
Avoid the standard American diet, which is problematic because it’s full of processed, packaged food that is convenient, inexpensive, and addictively tasty but unhealthy.
7. Prioritize Whole Foods, Shun Packaged
Recognize that different people thrive on different diets, but universally avoid packaged processed food for better health outcomes.
8. Avoid Foods With Cosmetic Additives
Minimize consumption of foods containing cosmetic additives (dyes, flavorants, gelling agents), as these ingredients are primarily used to enhance appeal rather than provide nutritional value, signaling ultra-processed food.
9. Re-engage With Food Preparation
Actively engage in preparing your own food and advocate for systems that make the acquisition and preparation of high-quality, nutritious food more accessible and affordable for everyone.
10. Embrace Dietary Resilience & Experimentation
Experiment with different diets to find what works for you, as humans are incredibly resilient and can thrive on various dietary approaches.
11. Healthy Low-Carb Or Low-Fat Both Work
Choose either a healthy low-carb or a healthy low-fat diet for weight loss, as both approaches can be equally effective when implemented with high-quality, whole foods.
12. Plant Proteins Are Complete
Dismiss the myth that plant foods are ‘incomplete’ or ‘missing’ amino acids; all plants contain all 20 amino acids, and strict complementing of beans and grains is generally unnecessary if overall protein intake is sufficient.
13. Redefine Protein Quality Holistically
When assessing protein quality, broaden your perspective beyond just amino acid composition and digestibility to include environmental impact and the presence or absence of other beneficial nutrients.
14. Diversify Grains, Reduce Refined Wheat
Consider reducing the intake of refined wheat, particularly the predominant type found in the U.S. diet, and explore heritage versions of different wheat grains and other diverse grain sources.
15. Evaluate Diets Fairly (Equipoise)
When comparing different diets, ensure each is implemented in its healthiest, most optimal form (e.g., healthy low-carb vs. healthy low-fat) to get a fair assessment of their true effects.
16. Excess Protein Not Stored
Understand that your body does not store excess protein for future use; any protein consumed beyond immediate needs is converted to other forms or eliminated.
17. Raw Milk Doesn’t Cure Lactose Intolerance
Do not rely on raw milk to cure lactose intolerance, as a study showed it provided no relief from symptoms compared to conventional milk.
18. Aspire To Healthful, Sustainable, Tasty Diet
Consciously choose foods that are healthful, environmentally sound, and tasty, aiming for a balanced approach that satisfies all three criteria.
5 Key Quotes
If you really look around the world, it is amazing how much variety there is in a diet that people can thrive on, except the one that doesn't work is the American diet, the standard American diet, because it's full of processed, packaged food.
Michael Pollan (quoted by Dr. Christopher Gardner)
No other mammal on the planet drinks the breast milk of another mammal to thrive later in life. So humans are the only ones who do it. It's really mostly cow milk. And it's kind of frigging bizarre, but it works for a lot of people.
Dr. Christopher Gardner
If you were to do one of these bomb calorimeter things that blew up and burned your whole body, minerals would be left. You can't get rid of minerals. And nitrogen is in that list. And so you can actually do a nitrogen analysis of food that you're eating and it will tell you how much protein is in the food.
Dr. Christopher Gardner
Bullshit. So I don't know if you can look at my paper in your podcast or show it. And I have it on my computer. We can provide links on the show note captions. So we wrote a paper in 2019. And this actually was pretty fun for me. It came from working with the chefs. The chefs were working on that protein flip idea that I mentioned earlier. And they were a little worried. They said, what is the thing about the plants missing the amino acids or being incomplete?
Dr. Christopher Gardner
I just love nutrition. It's really complicated, but it doesn't have to be. There can really be a lot more consensus than controversy if you can have this kind of exchange and explain some of the nuance behind it.
Dr. Christopher Gardner