In the last few editions of Pursuing Health Pearls we’ve been talking about the importance of metabolic health. In the coming months, we’ll explore some of the most important tools we have for improving metabolic health. We’ll begin in this edition with nutrition, which many would argue provides the cornerstone of metabolic health.
Before diving in, we also want to make it clear that we are very sensitive to the fact that not everyone has access to affordable healthy food, and we are actively working on exploring this issue as well as other social determinants of health on upcoming editions of the podcast.
This edition is in answer to the many questions we receive about nutrition, and provides an overview of the general framework we use. We attempt to break this complex and controversial topic down into simple pieces, some of which - such as mindful eating and food timing - don’t cost anything and are available to everyone.
Our intent is not to induce overwhelm, but rather to empower readers with information so that they can make more informed choices and implement small changes in a stepwise fashion. Although nutrition is incredibly personal, there are some general principles from which the vast majority of people benefit, and those are what we focus on here. Once these general principles are in place, a nutrition plan can be refined to meet individual needs with the help of an experienced clinician.
We find that for most people, working on them in this order leads to success, but every person is different and it’s always best to start in a place that feels right for the individual. We’ll review each of these 3 factors in detail here.
Refining food quality is a great place to start for many people. In this section, we’ll talk about:
When talking about food quality, it is important to first make the distinction between highly processed and real food. Processed food can be identified using a classification system called NOVA, which sorts foods based on the extent of processing. “Ultra-processed” foods are the most highly processed in this classification and are: “energy-dense, high in unhealthy types of fat, refined starches, free sugars and salt, and poor sources of protein, dietary fibre and micronutrients. Ultra-processed products are made to be hyper-palatable and attractive, with long shelf-life, and able to be consumed anywhere, any time. Their formulation, presentation and marketing often promote overconsumption.” Essentially, these are foods engineered by food companies to get you to purchase and eat more of them without regard for their nutritional value or impact on your health.
Real food, on the other hand, is food in its natural form, coming from the ground, a tree, or an animal. This is the food that has fueled our ancestors for hundreds of centuries.
You may be asking, “What’s the big difference between processed and real food? If they both provide calories, don’t they both give me the energy I need?”
This is a great question, but this is exactly where we’ve been led astray. At the end of the day we do need fuel in the form of calories, but in order for our bodies to function properly we need more than just calories, we need nutrients. Real food is different from processed food in that it is nutrient dense - it is packed full of the nutrients our bodies need to thrive. Remember that food does not exist just to make us feel full when we are hungry, it provides the building blocks for every cell in our bodies. It provides fuel for our microbiome to maintain a healthy gastrointestinal tract, and it provides information for our DNA, turning on genes that are important for our health. Without these nutrients, we are lacking very important ingredients needed for optimal metabolic health.
Notice that you didn’t see refined grains, potatoes, or any type of processed or packaged food on that list, because the nutrient density of those foods is much lower. Not only do processed foods lack the nutrients that our bodies need to function optimally, but because they are engineered to be hyperpalatable, they hijack our metabolism and influence us to eat more than we need.
Ultra-processed foods contribute to about 60% of total energy intake, and about 90% of energy intake from added sugars in the US. Additionally, ¾ of the population has an eating pattern that is low in vegetables and fruits, and most Americans have exceeded the recommendations for added sugars. From 2001-2004 Americans consumed 22.2 teaspoons of added sugar per day (that’s 355 calories per day just from added sugar!). This exceeds the WHO's 2015 recommendations for added sugar of no more than 5% of daily calories or about 6 tsp of added sugar per day, as well as the AHA’s 2009 guidelines recommending less than 6 tsp of added sugar for women, 3-6 tsp for children, and 9 tsp for men per day.
It’s important to note that added sugar has zero nutritional value, but is included in a majority of processed foods to make them hyper-palatable and addictive. What makes consuming so much added sugar so dangerous is that there is a significant association between added sugar consumption and increased cardiovascular disease mortality. Although the sugar industry tried to cover up this link for many years and shift the blame to fat instead, confusing the public, the link is now very clear.
So, if processed foods and added sugar are so bad for us, why is our consumption of these foods so high? In large part, our toxic food environment is to blame. The fact that these ultra-processed foods that have been engineered to be hyperpalatable are so freely available and constantly surrounding us make them nearly impossible to avoid.
Part of the reason these foods are so impossible to avoid is their addictive nature. In fact, one study demonstrated that the taste of sugar was more addictive than cocaine in rats, which are a well-established model for addiction research. Most mammals have evolved in environments where sugar was very rare, so we have an innate hypersensitivity to sweet taste. It is only recently in human history that we have had such abundant access to sugar and sweetness. Because we have such a hypersensitivity to sweet taste, the stimulation of our sweet receptors by sugar-rich diets which are now widely available sends a very intense reward signal to the brain with the potential to override self-control mechanisms and lead to addiction.
It is the addictive nature of ultra-processed foods and sugar that makes focusing on food quality such a great place to start. While consuming foods that are highly addictive and engineered to keep you eating more, in our experience it can be much more difficult to control food quantity or adjust food timing than while eating foods that are nutrient dense and satiating.
This is also a reason why so many diets are ineffective. Initially will power prevails, but no amount of will power can withstand the engineering that allows these foods to hijack our hormones and biochemistry to keep us eating more.
We believe the addictive nature of these foods should be taken seriously, in much the same way as addiction to any other substance. We personally believe anyone can benefit from removing all processed foods and sugar for a period of time, if they are willing. Thirty days is a good time frame, but as little as 10 days can also have the desired effect. Much like detox from alcohol or a drug, it’s difficult to think clearly and understand the impact the substance has on you until you have some distance. Symptoms including headaches, intense cravings, and irritability are common when initially coming off these substances, but after the first week or so most people are amazed to see how great they feel.
Once afforded some distance from processed foods and sugar, it is much easier to make decisions about how to incorporate them back into a diet long-term. Some people are able to eat these foods infrequently for certain occasions, acknowledging that although they don’t have much nutritional value they may have value in enjoyment or participating in social situations. Most of the time after eating these foods again we don’t feel so great and this can act as a gentle reminder that focusing on nutrient-dense foods makes us feel at our best. For others, even a small amount of these foods can be a slippery slope, and they opt to keep them out of their diets permanently. Again, this is an individual decision and one to experiment with over time.
Eliminating processed foods and sugar from the diet can also be a great opportunity to experiment with an elimination diet. Because proteins from certain foods such as gluten and dairy are commonly associated with intolerance resulting in symptoms that range from nasal congestion to gastrointestinal upset to joint pain, eliminating these food groups and re-introducing them to assess for the recurrence of symptoms can help to determine which foods each individual’s body tolerates best.
It can be easy to get carried away in the details, but it’s actually very simple to distinguish between real and processed foods. Here are some of the guidelines we use:
We’ve spent a lot of time distinguishing real from processed food, but there is another layer of complexity when it comes to quality. Unfortunately even when we choose foods in the categories of most nutrient-dense foods listed above - meats, seafood, vegetables, nuts and seeds, etc - they may still not have been cultivated in their natural environment which can affect their impact on health.
Much of the produce sold today has been grown in another climate halfway across the world, sprayed with pesticides, and then stored and shipped to your local grocery store. Several pesticides have been linked to cancer. Perhaps the most talked about recently is glyphosate, the active ingredient in RoundUp. Monsanto, the maker of RoundUp is facing tens of thousands of lawsuits and has already paid hundreds of millions of dollars in damages after glyphosate, the ingredient in it’s weed killer RoundUp, was linked to non-hodgkins lymphoma.
Many crops have also been genetically modified in order to withstand being sprayed with these pesticides. We don’t fully understand the long-term implications of genetically modified organisms or GMOs on our health yet.
Additionally, the longer produce is stored before it’s sold and consumed, the lower the nutrient content. One study showed that broccoli purchased in the supermarket in the fall when it is in season has twice as much vitamin C as when purchased in the spring after it had been shipped from elsewhere.
Here are two ways to combat these problems with produce:
Meat and seafood fall prey to similar issues with the way they’ve been raised. The topic of the role of meat in a healthy diet is a huge one in and of itself that we’ll save for another time, but for now we’ll suffice to say that meat is one of the most nutrient dense foods out there and an important source of complete protein. While it is possible to get enough protein and micronutrients from a diet without meat, it requires a lot of planning and attention to detail.
Just as with produce, there is a big difference between meat that is grass-fed and raised in its natural environment and meat that is processed or raised in factory farms and fed corn, soy growth hormones, and antibiotics. We think of meat that is raised in factory farms as another form of processing. Consuming meat that is raised in as close to its natural environment, if possible, is another way to increase nutrient density and real food consumption:
We covered a lot of ground here talking about food quality, and we believe fueling our bodies with the nutrients they need is one of the most important things we can do to support health and healing. This approach also allows us to focus on increasing nutrients rather than restricting calories.
The next factor we can consider when it comes to nutrition is food quantity. There are various ways to approach this with increasing levels of precision and we’ll review several of them here.
We find that by focusing on food quality first, many people tend to regulate their appetite quite well without having to worry about food quantity because real food is so much more satiating and they’ve gotten rid of the hyperpalatable and addictive foods that influenced them overeat. However, if someone wants to take their nutrition to the next level, thinking about food quantity can be a good next step.
There are two aspects to food quantity:
We’ll start with the simplest ways to think about food quantity and then we’ll add more precision as we go.
A very easy and simple way to take food quality into consideration is by building a plate that is balanced in macronutrients. As a general guideline, a plate filled with the proportions below can provide a generally balanced macronutrient intake:
Eating 3 meals per day using this as a general outline in addition to a couple of real food snacks (think: nuts or nut butter, fruit or vegetables, hard boiled eggs, hummus, or guacamole) can be a great start.
We also find that mindful eating can be very helpful for preventing overeating. Personally, we found that initially after making changes to the quality of our food choices we felt much better and more satiated. However, eventually there came a point where we would still overeat, even on these healthy foods. Usually this is due to boredom, stress, emotional eating, or just plain being distracted while eating. Mindful eating is the concept of focusing on the present moment and being in tune with thoughts, feelings, and sensations while eating. Mindful eating can be approached in the following ways:
Before we dive into weighing and measuring, we want to clearly state that there are some people for whom this approach might not be best for, particularly those who have a tendency toward disordered eating. Weighing and measuring can trigger patterns of disordered eating and for those individuals at risk it may be best to stick to general guidelines and following hunger cues.
For those who do not fall into that category and want to add some precision to their eating patterns, weighing and measuring is a way to do so. We would also like to note that weighing and measuring doesn’t have to be a long-term practice. Many people find that after measuring for a month or so they have a better understanding of portion sizes and how much food they truly need, and are able to “eyeball” portions moving forward. Measuring food quantity periodically from then on can be a good way to “recalibrate” your eye.
As we mentioned before, there are two measurements we’d like to focus on here:
Overall caloric needs can be estimated roughly or in a more precise way. Health.gov has a table with general guidelines for daily caloric intake depending on age, sex, and activity level:
There are also plenty of websites and apps out there which allow individuals to enter their weight, age, activity level and desired outcome and output an estimated daily caloric need.
This can also be made more personalized to the individual if their basal metabolic rate and activity level are known. Basal metabolic rate can be obtained by many of the body composition measurements we discussed in Ep 146 about metabolic health. These numbers can be plugged into an equation such as the Harris-Benedict equation which multiplies basal metabolic rate by an activity factor to determine caloric needs.
Overall, the method used is much less important than finding a starting place. Once tracking is started, caloric needs can be adjusted up or down to find the sweet spot based on how the individual's body responds and their goals.
The first step in defining macronutrient percentages is to determine daily protein needs. Daily protein needs again depend on the individual’s goals and activity level and can range anywhere from 1.2-2.7 g/kg of body weight per day (see table below). Examine.com provides an evidence-based protein intake calculator which some people may find helpful.
It’s important to note that the US Recommended Daily Allowance (RDA) for protein is 0.8 g/kg. This number represents a minimum intake to prevent malnutrition, and is not an ideal intake. Subsequent analyses of the same data used to develop the RDA showed a minimum protein intake of 1.2 g/kg/day to be more appropriate. Additionally, major organizations such as the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine recommend protein intake of 1.2-2g/kg of body weight per day to optimize recovery from training and promote growth and maintenance of lean mass.
Adequate protein is especially important in older adults. 40% of men and 55% of women over age 50 have sarcopenia, or impairment of physical function combined with a loss of muscle mass. This can lead to frailty, falls, fractures, and dependence on others ultimately potentially leading to the need to live in a nursing home. Older adults need to take in more protein at each meal in order to stimulate muscle synthesis than younger adults. It’s recommended that adults > 65 consume 1.0-1.2 g of protein per kilogram of body weight per day, and it is acknowledged that they may need up to 1.5 g/kg/day if they have acute or chronic diseases with the exception of kidney disease.
For many people, just determining and tracking total daily caloric needs or total protein needs may be enough precision. For those who want to refine their food quantity even more, the percentage of total calories comprised of the other two micronutrients, carbohydrates and fat, can also be monitored. After establishing total daily caloric needs and protein needs, all that is left is carbohydrates and fat. As a general guideline, a healthy, active person may choose to split the rest of the calories by percentage in half. For example, if protein intake composed 30% of total calories, carbohydrates and fat would then each make up 35% of total calories per day for a total of 100%.
This is a good general starting place for those who are generally healthy and active, but is something that should be experimented with on a personal basis to determine what ratio works best. If an individual is less active, aiming for fat loss, or has signs of metabolic dysfunction, they may benefit from decreasing the percentage of carbohydrate and increasing the percentage of fat. On the other hand, someone who is much more active may do better with a higher percentage of carbohydrates. Working with a personal dietitian or physician is recommended to determine the right macronutrient percentages based on an individual’s health conditions and goals.
The extreme version of a low carbohydrate/high fat diet would be a ketogenic diet, in which carbohydrates contribute less than 5-10% of total daily calories. The goal of a ketogenic diet is to achieve nutritional ketosis, which is characterized by a certain level of ketones circulating in the blood that then provide energy for the body. This diet is currently being explored in a number of conditions such as epilepsy, diabetes, metabolic syndrome, cancer and neurodegenerative diseases such as Alzheimer’s. Implementing a ketogenic diet would be an example of adjusting macronutrient ratios for a therapeutic effect. It’s important to note that changing one’s diet for a therapeutic effect like this should be done under the supervision of an experienced physician or dietitian. We’ve talked about ketogenic diets in previous episodes of the podcast, for example with Dr. Dom D’Agostino in Ep 120.
The third and final factor that can be refined when talking about nutrition is timing. Depending on the person, timing may be a more accessible place to start because it is relatively simple and doesn’t involve a lot of planning or big changes to food choices, shopping, or cooking, but can still have a big impact.
Again there are two different factors we will discuss when it comes to timing:
Of the 3 macronutrients, carbohydrates are the most hormonally active and sensitivity to carbohydrates changes based on the time of day and activity.
All of our bodily functions operate on a 24-hour circadian clock, which is largely set by the light and darkness our eyes are exposed to and when we eat or don’t eat. In the simplest terms, when our bodies know we are awake based on external signals such as light, food intake, and activity, certain genes are upregulated in order to support metabolism. As a result, glucose tolerance, or the ability to regulate blood sugar after consuming carbohydrates is higher in the morning than the evening. For this reason, focusing on taking in more carbohydrate-heavy meals in the morning and less in the evening may be beneficial.
Carbohydrate intake can also be timed relative to activity. It is known that glucose tolerance increases during and after exercise. During exercise while muscles are contracting, they can take up 50 times more sugar from the blood without the need for insulin. Muscle tissue is also more sensitive to insulin after exercise. Because of these effects, some advocate consuming the majority of carbohydrates for the day within a 3 hour window after exercise. For endurance exercise events more than 2 hours in duration, consuming carbohydrates prior to exercise has been found to be beneficial to performance. Finally, consuming carbohydrates solely or in combination with protein during resistance exercise sessions has also been shown to improve adaptations.
Protein intake can also be timed relative to activity. While it’s true that consuming protein within 2 hours after a workout increases muscle growth, it seems to be more important to get enough protein throughout that day. In fact, muscles remain sensitized to protein for at least 24 hours following a resistance training session. Consuming 20–40g of protein every 3-4 hours improves muscle growth rates when compared to other ways of eating and is associated with improved body composition and performance. Additionally, consuming 30-40g of casein within 30 min of sleep may also improve strength and muscle growth.
Fasting is a very popular topic these days, and there is good reason why. There are many different ways to approach fasting and to use it strategically for a therapeutic effect or to promote health. This is another area that should be used with caution in certain populations, including those who have a history of disordered eating, children, and pregnant women.
First we’ll review what is known about why periods of fasting can have a positive impact on our metabolic function. As discussed above, our bodies operate on a 24-hour circadian clock which coordinates changes in many different areas of our bodies so that we can metabolize the food we are taking in during the day. One of the signals that helps to set this circadian rhythm is food intake. However, during periods of prolonged fasting >8 hours, our metabolism adjusts to minimize processes that have to do with growth, and instead favors processes that involve maintenance and repair, enhancing our resistance to stress, recycling damaged molecules, improving glucose regulation, and suppressing inflammation. One can imagine that without periods of prolonged fasting, our bodies are not given adequate opportunity to do maintenance and repair, recycle damaged molecules, and enhance resistance to stress that is necessary for optimal metabolic function and health. One study found that more than half of adults eat > 15 hours per day, which limits the time spent in a fasted state during which this maintenance and repair can take place.
Fasting has been studied in humans and found to improve a variety of different conditions including obesity, insulin resistance, lipid abnormalities, high blood pressure, and inflammation. [1, 2, 3, 4, 5] These are essentially all of the factors we talked about in our last Pearls episode that are associated with metabolic syndrome. Fasting has also been shown to enhance parasympathetic tone and increase heart rate variability, and intermittent fasting is also thought to repair metabolism in cancer cells inhibiting their growth and making them more susceptible to treatments.
There are several ways to incorporate periods of fasting, which can be seen in the table below:
A fasting-mimicking diet, characterized by reduced calorie intake for 5 days monthly for 3 months has also been shown to provide many of the benefits of fasting for general health and a variety of health conditions. We discussed this diet in detail in Ep 112 of the podcast with Dr. Valter Longo.
In summary, we’ve reviewed our general approach to nutrition covering the factors of quality, quantity, and timing. We attempted to make this complex and controversial topic as simple as possible. Although most people can benefit from simple changes to nutrition such as eating real food, avoiding overeating, and incorporating regular periods of fasting, nutrition is highly personal and changes through different phases of life. Working one-on-one with a dietitian is a great way to personalize a nutrition plan to meet individual needs.
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Disclaimer: This podcast is for general information only, and does not provide medical advice. We recommend that you seek assistance from your personal physician for any health conditions or concerns.