by Siim Land
Most commonly, the idea of eating meat gets juxtaposed with a plant-based vegan diet devoid of all animal foods that’s depicted as the epitome of a healthy diet. However, there is no data to prove that. Generally, there are no differences in mortality between vegetarians and omnivores[496].
Those who eat more red meat also have a tendency to smoke, drink, eat fewer vegetables, and engage in other unhealthy behaviors that increase their risk of cancer. This has been proven by many studies[497][498].
People who follow a vegan diet already are simply more mindful of their health if they’ve taken the dietary path they’ve chosen. Likewise, a person eating meat and fat can be equally as healthy if they pay attention to these things. Studies that compare vegetarians and omnivores with the general population see both groups living longer than the average person[499].
You can be equally as healthy and equally as diseased on a vegan diet as on a meat-based diet. The determining factor lies in how your body uniquely responds to the food you eat, what other habits you follow, and the general lifestyle. That’s why everything regarding nutrition and longevity is context based. Large epidemiological studies that cover large populations are quite arbitrary unless they target a specific way of living that you could identify with.
Meat Myths
Meat and animal foods are thought to increase tumor formation and cancer because of containing certain substances such as Neu5Gc. Eating meat is also thought to be pro-inflammatory and thus dangerous. However, anthropological data in the example of the Masai who eat primarily meat, blood, and milk, don’t show these people having inflammatory diseases. It might be that the inflammation is caused not by the meat but the other things such as bread, starch, sugars, or oils. Eliminating those carbohydrates and increasing meat consumption has been shown to actually reduce inflammation markers[500].
Another dangerous chemical that’s received some recent attention is TMAO (trimethylamine N-oxide) that’s thought to increase the risk of heart disease[501]. However, studies haven’t shown that red meat increases TMAO. In fact, a 1999 study found that out of 46 different foods fish was the only one that raised TMAO. Trimethylamine occurs naturally in seafood[502]. Now hold on a minute…if fish is considered the “heart-healthy” alternative of meat for protecting against heart disease, then how come it’s high in TMAO that also raises your risk of heart disease? Clearly, the roles of these compounds are misunderstood and taken out of context in attempts to point the finger at certain food groups while being biased with others.
Figure 69 Compared to fish and seafood, meat and dairy are almost devoid or TMAO
Let’s look at some more myths about meat consumption...
Meat is high in protein and eating too much protein is thought to cause kidney disease. Kidneys excrete nitrogen by-products from digesting protein, thus too much protein over-taxes the kidneys. High protein diets may be harmful to those who already have kidney disease but there’s no evidence they damage healthy individuals[503]. This idea of protein causing kidney disease may be over-exaggerated by diets that combine protein and meat with different inflammatory foods like grains or vegetable oils.
What about nitrates? More chemical compounds that are said to be harmful to us. Usually, nitrates are added to processed foods and meats as to preserve them longer. However, nitrates are found in many other foods and they’re produced by our bodies as well. Most of the nitrates you get actually come from vegetables and greens. Did you know that one serving of arugula, two servings of butter lettuce, and four servings of celery or beets all have more nitrites than 467 hot dogs[504]? Obviously, the celery and arugula are healthier than hot dog meat despite their higher nitrate content. Your saliva is also incredibly high in nitrites. So, if you’re worried about the nitrites in meat, you should focus your efforts on not swallowing that much.
Neither nitrates or nitrites get accumulated in the body. Nitrates from food get converted into nitrites after coming into contact with our saliva. About 25% of the nitrate we eat gets converted into salivary nitrite, 20% gets converted into nitrite, and the rest gets excreted in the urine within 5 hours of ingestion[505]. Studies show no association between nitrites in diet and stomach cancer[506]. What’s more, nitrates may also help boost the immune system and protect against pathogenic bacteria[507][508], which is why arugula is a good ingredient to add to your diet.
Meat itself is actually one of the superfoods of the planet that helped our species to evolve. Red meat is a very rich source of essential vitamins and minerals, especially B vitamins. Vitamin B12 is vital for proper nervous system functioning and general muscle homeostasis. B12 deficiencies can cause accelerated aging, neurological disorders, cardiovascular disease, sarcopenia, and many other ailments. Red meat is also a highly bioavailable source of vitamin D, iron and zinc, which are important for other metabolic processes. It has magnesium, copper, phosphorus, chromium, and selenium. Although some plants such as spinach are high in iron, the body can absorb only about 2-7% of the iron, whereas it can absorb 20% of it from red meat[509].
Aside from all the ethical and environmental implications, meat is an incredibly bioavailable source of most of the vitamins and minerals you need. It also covers the aspect of anabolism and protein, which are needed for maintaining lean tissue as you get older. But as with all things in nature, there are no free lunches and meat isn’t that kind of a superfood you could eat in unlimited amounts and stay healthy.
As we’ve touched upon before, amino acids and protein, primarily from meat, will stimulate the mTOR pathway and make you anabolic. This will trigger muscle protein synthesis and makes every cell in your body grow, including cancers and tumors. Overexpression of mTOR or its dysfunction is often related to various cancers and genetic disorders[510]. There’s no denying that mTOR is an all-encompassing anabolic switch that makes everything grow – the good and the bad.
You don’t want to be under the influence of mTOR because of eating meat breakfast, lunch, and dinner. You definitely don’t want to become deficient of it either by fasting too long or eating only low mTOR foods. People who are afraid of IGF-1 and go on fully plant-based diets with low protein tend to deteriorate quite rapidly unless they specifically supplement that.
As is stated throughout Metabolic Autophagy, you want to strike somewhat of a balance between stimulating mTOR with exercise and protein but not too much because it’ll accelerate aging. The breach for crossing the chasm again is intermittent fasting and resistance training.
All of the research on eating meat, eggs, saturated fat, cholesterol, and carbohydrates has been done on people who aren’t practicing intermittent fasting. There are virtually zero studies on individuals who follow a fasting focused lifestyle and are engaged with other healthy lifestyle habits like resistance training, hormesis, and calorie cycling.
Of course, over-expression of mTOR and protein can be bad for you if you’re eating the standard diet with super high meal frequency. However, if you’re already fasting ala Metabolic Autophagy style, you’re changing the context of the situation completely. When you come from a fasted state or after you’ve exercised, you want to stimulate mTOR for recovery and muscle growth. In that situation, meat, protein, and mTOR are pro-longevity – they’re good for you because otherwise, you’d experience sarcopenia.
If you use mTOR and protein consumption strategically as to support muscle growth and recover from fasting, instead of fat gain and caloric fillage, then that mTOR stimulation is actually helping you to live longer. Shocker, I know.
Chapter XI
The Case Against Sugar (and Fat)
“Any diet can be made healthy or at least healthier,
from vegan to meat-heavy,
if the high-glycemic-index carbohydrates and sugars are removed,
or reduced significantly.”
Gary Taubes
Despite the prominence of the diet heart hypothesis throughout the 70s and 80s, there were some contradicting voices in the medical community. In 1972, a
physician named Robert C. Atkins wrote a best-selling book called Dr. Atkins’ Diet Revolution.
Essentially, the Atkins Diet is a low carb diet that prohibits the consumption of carbohydrates and allows unlimited protein and fat. It’s said to result in rapid weight loss as long as you stick to those guidelines. Indeed, a lot of people did find success with this way of eating. Because of the higher intake of protein and reduction in carbs, it’s very easy to consume fewer calories and still feel satiated.
During its inception, the Atkins Diet was demonized as unhealthy and dangerous due to the high saturated fat content. Even today there are people saying animal fats are bad. However, current data hasn’t found any correlation between saturated fat and heart disease[511]. In fact, it’s thought that the studies that made those claims in the past suffered from potential biases and selective reporting of results[512].
Nowadays we know that both low-carb, as well as low-fat diets, can be effective for weight loss and improving metabolic health[513]. Which one works better is more a matter of context.
Of course, an Atkins or a ketogenic diet can lead to some serious medical conditions like diabetes and heart disease. Not because of the dietary mechanisms of the diets but because of the individual who’s doing it. Some people may indeed react negatively to consuming saturated fat or they may have other poor habits.
It’s important to remember that the combination of certain foods may cause a completely different metabolic reaction than eating those same foods alone. For instance, as we remember from the chapter about glucagon and autophagy, consuming protein in a fasted state or on a low carb diet doesn’t raise insulin and actually lowers the insulin-glucagon ratio. Combining protein with carbohydrates spikes insulin through the roof and makes the entire meal more insulinogenic. Furthermore, you can indeed promote oxidative stress in the body by consuming oxidized fats and cholesterol or if you end up glycating them with glucose (more on this down the line).
Any diet you follow, whether that be Paleo, vegan, keto, SAD, or omni-lacto-vege-pescetarian, can be equally as unhealthy and dangerous if you fail to understand the underlying metabolic reactions that occur. What foods you eat, what ingredients you combine them with, when you consume them, how much, at what frequency, your methylation status, and overall biomarkers will determine the final nutritional result. It doesn’t matter what diet you’re on. What matters is how you choose to manipulate nutrient signaling, hormonal profile, and meal timing. That’s what Metabolic Autophagy seeks to teach you.
The Carbohydrate-Insulin Hypothesis
Atkins wasn’t definitely the first person to promote a low carb high fat diet. It was actually the norm to prescribe it to obese people back in the day. In 1825, Jean Anthelme Brillat-Savarin wrote:
The second of the chief causes of obesity is the floury and starchy substances which man makes the prime ingredients of his daily nourishment. As we have said already, all animals that live on farinaceous food grow fat willy-nilly; and man is no exception to the universal law.[514]
One of the earliest of such dieticians was an English undertaker named William Banting. He was previously obese and failed to lose weight numerous times. In 1863, Banting published a booklet called Letter on Corpulence, Addressed to the Public, in which he outlined his diet program[515]. The man ate primarily meat, green vegetables, fruit, and dry wine. He avoided sugars, starches, beer, milk, and butter, which tend to be quite fattening. Nowadays, most low-carb paleo diets follow a similar template with slight differences.
In his books, Arkins made the bold statement that avoiding carbohydrates produces a metabolic advantage because burning fat burns more calories. However, that is not the case as fats and lipids have the lowest thermic effect of food (3-7%), compared to carbs (5-10%) (See Figure 70). The weight loss was probably due to higher protein intake with a 20-30% loss of calories to metabolism. Most diets similar to Atkins, such as The Zone and Protein Power tend to be the same.
Figure 70 The Thermic Effect of Different Macronutrients
In 2002, an American journalist and author Gary Taubes wrote an article in the New York Times Magazine called What if It’s All Been a Big Fat Lie?[516]. He starts off with questioning the US medical establishment and their 30-year long ridicule of Atkins, calling it quackery and fraud. Taubes also makes the claim that the low fat high carb dietary recommendations are the cause of the obesity epidemic in America and that Atkins was right all along. Bold statements indeed.
Taubes does make a good point that despite the introduction of the low-fat guidelines after the 70s, the obesity epidemic took off into even greater heights around the early 80s. Despite smoking less and eating foods devoid of cholesterol, heart disease and metabolic disorders haven’t still declined.
Unfortunately, we live in what Kelly Brownell, a Yale psychologist, has called a ''toxic food environment'' of cheap food, empty calories, super-size portions, clever marketing and sedentary lifestyle. That’s why the average person in Western countries finds it difficult to lose weight or stick to their diet – their willpower has waned off. However, it’s not just that people are eating too much and moving too little. There is another potential metabolic mechanism at play that unfavours the obese and healthy.
In 1920, the Canadian physician Sir William Osler wrote in The Principles and Practice of Medicine that most of the doctors in early 1900s considered refined carbs and starches as the primary drivers of obesity[517]. It was common sense back in the 40s and 50s that the most fattening foods were sugars, sweets, and carbohydrates.
The physiology of how insulin promotes weight gain dates back to the 20s when insulin was first discovered. Patients who are underweight tend to be given additional glucose and insulin injections to fatten them up to a healthy range. Type-1 diabetics who take insulin more often will gain more weight[518]. Bodybuilders trying to gain mass also inject themselves with insulin so they could build muscle. Insulin, after all, is a storage hormone that directs nutrients into cells.
The idea that weight loss is simply a matter of calories in vs calories out does not hold water if you put it to serious test. We already showed in the chapter of Anabolic Fasting that it’s possible to build muscle and lose fat at the same time with proper nutrient partitioning and meal timing. Body composition is regulated mostly by hormones and the macronutrient ratios of what you eat and when you do it.
Intensive injections of insulin several times a day make diabetics gain weight quite rapidly. In a study by Henry R. R. et al (1993), they took 14 diabetics and gave them insulin over a 6 month period. The patients’ bodyweight increased on average by 8.7 kg (19 lbs) despite eating 300 fewer calories a day[519]. They were consuming less food but because of the higher levels of insulin, they still gained quite a lot of weight. That’s what many yo-yo dieters who eat a low-fat but high carb diet tend to fall into as well. They’re keeping themselves in a state of hyperinsulinemia and thus never tapping into their own body fat stores.
On the flip side, medical drugs like metformin and rapamycin can treat insulin resistance and make the person lose weight. In type-1 diabetes, the pancreas doesn’t produce enough insulin, which keeps the blood sugar elevated for longer. If the person isn’t injecting insulin their insulin levels will drop extremely low. It’s very common amongst type-1 diabetics to suffer from severe weight loss. That’s why they get injected with insulin – not only to raise their insulin but to also prevent deterioration. The mechanism for insulin-driven weight gain is very well documented.
Insulin is the main regulator of energy storage and body weight homeostasis. It promotes weight gain but also makes you become more hungry and eager to eat. Whenever your glucose drops you want to eat again to prevent hypoglycemia. If a person eats a low-fat high carb diet, then that’s going to end up with another rise in insulin, keeping them in a state of chronically elevated insulin (hyperinsulinemia). High meal frequency is as bad as high carb intake both because of hyperinsulinemia and no opportunity to enter autophagy.
O
besity as a disease is primarily a hormonal issue. Fat gain is mostly stimulated by insulin, which will make the body store the food you eat. There are also issues with leptin resistance and chronically elevated cortisol. These hormones signal the person to follow certain behaviours that make them eventually obese, such as binge-eating, become sedentary, or not feel satiated after meals.
Cortisol is the body’s main stress hormone that releases adrenaline and breaks down glycogen stores to supply the blood with glucose. Chronically elevated levels of cortisol not only lead to fatigue but can also promote weight gain. Cushing’s Disease makes the body overproduce cortisol which results in weight gain. On the flip side, Addison’s Disease makes the adrenal glands produce less cortisol, which results in weight loss.
The reason excess cortisol makes you fat has to do with high blood glucose and consequently elevated insulin. If you’re stressed out or have entered the ’fight or flight mode’, you’re more prone to store fat because of shutting down digestion and raising insulin. The body wants to supply its muscles to run away from danger and fat loss becomes a secondary goal.
Figure 71 Spiking insulin raises cortisol, which promotes fat gain
Chronic stress promotes chronically high blood sugar and hyperinsulinemia. We also know that insulin resistance walks hand in hand with leptin resistance, that makes the brain desensitized towards satiety signals from food. This is often accompanied by emotional binge-eating, stubborn fat loss plateaus, and less satiety signaling.
Paradoxically, people who are overweight i.e. fat cells are overly full also have higher levels of leptin. That’s why they continue to overeat and gain weight despite already having enough energy around – they’re brain doesn’t get the message.