Here is what I’ll cover in this post:
- Dr. Z discusses his nutrition philosophy
- What is considered “unhealthy” for longevity
- What is considered “healthy” for longevity
- Review of various popular “diets”
- Dr. Z’s Recommendations
Dr. Z on Dieting
People ask me about dieting all the time, both as a peer and as a professional. What’s the best diet right now? Which diet is the worst? What diet best supports my exercise routine? Which diet is right for my kids? It’s difficult for me to recommend one single diet without elaborating on nutrition as a whole, so allow me to respond to some of the most common concerns I hear.
First of all, I hate the word “diet”. This implies that a person starts eating a certain way, and then at some point in the future stops. I prefer to think of it as a long-term nutrition plan. Nutrition needs to be deliberately and intentionally planned – leaving it up to spur-of-the-moment decisions is a recipe for disaster. However, for the sake of brevity, “diet” and “eating plan” will be used interchangeably here.
Second, there is so much debate about what is and isn’t healthy to eat. Don’t even get me started on the debate about when to eat. There is also confusion around terminology. For example, everyone seems to know that excessive sugar intake is bad. However, there is no universally accepted definition of “excessive”.
Lastly, there does not seem to be a “one-size-fits-all” way of eating. Different people have different goals, and various goals have different nutrition requirements. There are also people who have various intolerances or allergies, as well as ethical or religious considerations that make otherwise healthy foods unhealthy or inedible. For the sake of simplicity, this article is going to focus on the goal of maintaining a healthy weight in a person who is moderately active and is looking to adhere to a nutrition plan that has the potential to minimize or reduce the likelihood of developing chronic diseases.
Diet & Nutrition
There are many nutrients that are considered “essential” – the human body cannot (or has limited capacity) to synthesize these and therefore we are completely dependent on consuming them in our diet. There are 21 amino acids that make up protein – 9 are considered essential, and 6 are considered conditionally essential. There are dozens of different fatty acids, broken up into 4 categories. Only 2 fatty acids within the polyunsaturated fat group are considered essential. Carbohydrates are considered non-essential – in theory, we can make all the carbs we need from protein and fat.
I want to start with what is mostly agreed upon as being unhealthy:
- Eating too close to bedtime
For the vast majority of people, this seems to be a bad idea since it affects quality of sleep - Foods with excessive sugar
I will define “excessive” in this case as a meal or a dish where one of the main ingredients is sugar, or a sugar derivative, which causes a “spike” in blood sugars and insulin levels within 2 hours of consumption
Examples: cakes, pies, pastries, any kind of sweetened beverage, etc. - Foods with excessive simple carbohydrates
Simple carbohydrates get converted to glucose quickly in the stomach and small intestines and can be as damaging, or even more damaging, then foods with excessive sugar
Examples: foods made mainly with rice, corn, wheat, potatoes - Consuming excessive calories
No matter the composition or source, too many calories usually leads to weight gain over time - Consuming excessively processed foods
There seems to be a very fine line between minimally processed and excessive – so this is the most subjective of them all
The general rule: most packaged foods that have more than a few ingredients should be avoided - Alcohol consumption
From a longevity standpoint, evidence is mounting that no amount of alcohol is “healthy”
Here is what is considered to be healthy:
- Vast majority of vegetables, or any foods that are considered a vegetable nutritionally
- Nuts and seeds
- Mushrooms
- Healthy protein sources
- Healthy fat sources
- Fruit, in moderation, with a focus on low-glycemic fruit
Now let’s look at these guidelines as compared to some of the most popular diets out there now.
Diets in Review
Carnivore Diet
Consists of eating nothing but animal products such as meat, fish, eggs, dairy. It eliminates everything else.
Dr. Z’s Take: Some people report doing really well on this diet – at least initially. This leads me to think that it might be useful for short term use for certain people – perhaps assisting in a form of elimination dieting or some form of detoxification. But it lacks so many essential nutrients that it simply is not compatible with a long term healthy eating plan.
Low-Fat Diet
This was a craze back in the 70s and 80s – removing fat from everything since fat was wrongly thought to be the villain.
Dr. Z’s Take: I don’t think any serious medical professional would recommend this way of eating any longer. One obvious issue was that fat was replaced with carbohydrates. Additionally, saturated fat was replaced with trans-fats. Also, most foods higher in protein also tended to have fat and therefore were avoided – leading to a low fat, low protein, high carbohydrate diet = a recipe for all the major chronic diseases.
Vegan Diet
Consists of eating nothing that has any kind of animal origin.
Dr Z’s Take: While the idea is enticing since plant-based foods tend to be among the healthiest, humans are historically omnivores. Our entire digestive system – from the teeth all the way down to our large intestine, were designed to incorporate animal products. Also, it can be very difficult to be completely vegan and adhere to the healthy eating guidelines. Eliminating all animal sources usually requires a heavier reliance on excessively processed foods, especially when it comes to getting enough protein. Also, there are many animal-only nutrients that are critical for health – such as Vitamin B12, but there are many others and some that we might not even know of yet. There are many people who report great results when first starting out on a vegan diet – which leads me to believe that it might assist with detoxification, similar to what is seen in the polar opposite Carnivore Diet. Overall, however, my professional opinion is that Vegan Diet is not optimal for long term health and longevity.
Vegetarian Diet
Consists of eating anything except animal flesh.
Dr. Z’s Take: Much less restrictive than Vegan Diet with fewer issues when it comes to critical nutrients. However, consuming enough protein is still a challenge while also avoiding heavily processed foods.
Ketogenic Diet
Consists of a very low carbohydrate, moderate to low protein, and high fat intake. The idea is to keep carbohydrate intake low enough to induce ketosis (not to be confused with the life-threatening ketoacidosis), since ketones serve as an alternate energy source for cells during times of starvation (or intentional ketosis).
Dr Z’s Take: For patients with certain metabolic or medical issues, following a ketogenic diet can have many benefits. However, its long term use can be problematic as it tends to be too restrictive when it comes to some vegetables, fruit, and other nutrients. Also, it is very difficult to adhere to long term – and even a slight deviation tends to take a person out of ketosis – thereby eliminating what is thought to be the biggest benefit of this diet (yet most of the restrictions are still in place). Many who try the ketogenic diet do not realize that they need to also restrict their intake of proteins since too much protein can be converted into carbohydrates and therefore kick a person out of ketosis.
Paleolithic (Paleo) Diet
Consists of eating foods that are thought to have been eaten by humans prior to modernity, or prior to the widespread use of agriculture. Typically, this means eliminating all modern forms of grains (wheat, corn and rice mainly), and all excessively processed foods. Some variations of this diet also eliminate dairy products (many people mistaken eggs as being a dairy product) – with the idea that ancient humans could not chase down wild cows to milk them.
Dr. Z’s Take: This is the eating style that I personally try to adhere to and tell patients to strive for. There are several caveats:
There is no universally accepted set of foods that are considered “prehistoric” since humans typically ate anything and everything they could hunt, gather, or fish. The focus should be on what they could NOT have gotten their hands on (i.e. modern grains, dairy, and processed foods), rather than debating the details of what ancient humans actually ate.
Men typically equate Paleo with “Caveman” and seem to feel the urge to beat their chest and load up on steak and bacon. However, Paleo done properly focuses on nutrient dense foods such as vegetables, nuts, seeds and mushrooms. Animal protein should be eaten in moderation – with occasional meat indulgences being just fine (yes, you can attend your friend’s BBQ party – but skip the booze).
Some populations seem to do just fine with dairy products – likely due to when domestication of lactating animals was introduced into their culture and ancestry. My general rule is that if a person belongs to an ethnic group where lactose intolerance is historically prevalent (>50% of the population), then dairy is probably best avoided.
Mediterranean Diet
A way of eating that tries to mimic the foods and dishes found in countries bordering the Mediterranean Sea (Greece, Italy, etc.)
Dr. Z’s Take: This is probably the most studied dietary intervention and seems to provide health and disease prevention benefits in all the studies that I have seen. So why don’t I recommend it? I call it the “Olive Garden Syndrome” – people tend to associate the Mediterranean Diet with the endless basket of breadsticks, piles of pasta, and loaded pizza pies served at most Italian-style restaurants. However, this is totally missing the point. The advantages of the Mediterranean Diet seems to be its emphasis on vegetables, olive oil, and fish. I would actually argue that the positive health benefits from these foods seem to outweigh the detriments of grains – more on this below. If you take out the grains, then you’re left with – you guessed it – the Paleo Diet!
To Whole Grain or Not to Whole Grain
There seems to be an obsession with grains, specifically whole grains, in the medical community. If you recall the old food pyramid, it recommended 6 to 11 servings of grains per day as part of a “balanced diet” (and they wondered why so many people have chronic diseases!). Grains, or precisely cereal grains, tend to be high in starch and poor in many nutrients. In fact, so poor in nutrients that they need to be fortified with nutrients to prevent diseases of acute deficiency (such as folate and neural tube defect) – to say nothing about chronic nutrient deficiencies. If you consider the amount of health-damaging starch you would need to consume just to get small amounts of nutrients and fiber – it’s a fool’s bargain. Grains allowed humans to transition from hunter-gatherers to cities and civilizations. Grains are very good for providing cheap and easy calories for a large number of people, and to support a very quickly growing population (and large armies). It is thought that the introduction of grains to human societies led to the degradation of human health on many levels.
So why do whole grains get such glowing endorsements from so many medical establishments? It’s all relative. Every single study I have seen that promotes the health benefits of whole grains compares whole grain with non-whole (commonly referred to as white) grains. So whole grains are, in my opinion, less health damaging then non-whole grains, but that isn’t saying much. Humans are much better off skipping grains whenever possible for much more nutrient-dense, health promoting foods (and leaving grains in storage silos for when famines hit – and hope it never does…)
Meat & mTOR
There is a debate about animal protein and its effect on mTOR. The Mechanistic Target of Rapamycin (mTOR) is a nutrient- and energy- sensing protein complex that helps regulate cellular metabolism. For the sake of simplicity, activating mTOR encourages protein synthesis, cell growth and division along with other growth related processes. Inhibiting mTOR puts the brakes on growth and activates pathways related to housekeeping and recycling. One of many signals that can activate mTOR is an abundance of branched-chain amino acids (BCAAs).
These BCAAs are much more abundant in animal sources of proteins than plant protein sources (which is why weight-lifters consume so much chicken breast or whey protein shakes). Constant activation of mTOR, however, is thought to be bad for longevity as it promotes many diseases of aging, such as dementia. On the other hand, suppressing mTOR all the time leads to a state of immune deficiency and can be equally lethal.
To make the situation more complicated, there are other factors that modulate mTOR, such as insulin, IGF-1, and probably others. So here is the conundrum: if a person consumes too much animal protein, they are over-activating mTOR which leads to chronic disease. However, avoiding animal proteins (which, as stated above, is the easiest way to obtain the essential amino acids and nutrients) can lead to malnutrition, as well as over-reliance on starch-rich foods that can drive up insulin and IGF-1.
The solution: like all things in life – moderation, and a careful attention to what is healthy and unhealthy for a person’s particular needs.
Final Thoughts
We all need to eat. So then it becomes a matter of choosing foods and meals that are health-promoting, and limiting foods that are disease-promoting. I personally do not let perfect be the enemy of good – there are certainly times when I indulge in foods that I know are not aligned with the information above – and it might shave a few seconds off my life. But, humans are not machines and food is not simply fuel. Eating and enjoying meals have a variety of social and cultural nuances to them that cannot be captured in any article or even volumes of books on nutrition. These nuances add flavor and enhance the quality of life. If done correctly, you can have your Paleo-friendly cake and eat it too.
Note: The above statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.