Optimize Your Nutrition With Exercise

Illustration © D. Yael Bernhard

Note to readers: You can listen to this article instead of reading by clicking on the article voiceover above.

“Our genome expects frequent exercise in order to sustain life.”

– Dr. David Perlmutter, Grain Brain

The screen on the elliptical treadmill had just registered one mile when I felt a tap on my shoulder. “I’m sorry,” said the gym manager, “but we’re having a water emergency. We will have to close the gym in twenty minutes.”

Twenty minutes! I still had two miles to go to complete my run, plus I wanted to use the weight machines. I wouldn’t have time to finish my routine. Now what?

Determined to make the most of the remaining time, I started brainstorming. How could I put this pattern interruption to good use? I bumped up the resistance on the treadmill by three levels and sprinted, knowing I wouldn’t be able to sustain it for long. Breathing hard, I completed one more mile, then jumped off. For once, I wasted no time checking emails or fussing with music before moving on to the weight machines. I made a short visit to each machine, using more weight and fewer repetitions. The game was this: if I could finish one quick round of all eight machines, I’d be rewarded with a second round.

Rewarded? Many people think of exercise more like a chore. But after almost fifty years of regular movement – swimming, hiking, running, walking, rowing, and African dance – I’m addicted to the feeling of satisfaction that follows my workouts. It’s subtle, but real, and worth the time and effort. As a health coach, I’m also aware of the many benefits of exercise, so I keep my eye on that prize when I feel resistance. When obstacles get in my way, I have a reservoir of positive experience to draw upon, and find a way to keep going. If my energy is low when I get to the gym, I start with rowing – an easy way to get my blood moving – or I search for a new playlist. Changing your pattern keeps things fresh.

The experiment at the gym led to a lasting change in my workouts, bringing more interval training into my routine. Ending my run with a high-intensity sprint is the new normal, and I frequently make two short rounds of the weight machines rather than lingering longer on each one.

This is the kind of self-talk that makes exercise into a priority. “When in doubt, work out” is my motto. Just as I always find time to eat, no matter what the weather or how much deadline pressure I’m under, I find a way to exercise. Even if I can only manage a 20-minute walk with my dog, movement is part of my daily life, and no day is complete without it.

Most people are aware of the most common benefits of exercise. We know it strengthens the heart and gets blood pumping. But have you considered that a cardiovascular workout increases the circulation to the tiny capillaries in your retina? We know working out helps us lose weight, but did you know exercise modulates your body’s ability to burn fat? Even with restricted calories, a sedentary metabolism is not trained to work efficiently, but a body that moves learns to make the most of stored energy.

Just as we need the right shoes and equipment in order to work out, it’s helpful to have the right facts to motivate our minds. This article explores the effects of exercise on nutrition, and the many rewards you can expect. If you are over the age of 50, this information is especially relevant for you. Here’s why:

Muscles Make Your Metabolism

Muscle is known as “the currency of healthy aging,” for good reason. Muscle is made of protein, and when you are young, protein synthesis is driven by hormones, particularly growth hormone. Growth hormone peaks around the age of 18, and then gradually subsides. By the time you reach middle age, protein synthesis has significantly slowed, and is no longer hormonally-driven. Now your muscles need to be used in order to switch on protein synthesis (and they need the right proteins, including leucine, the amino acid found in animal-derived protein, which activates protein synthesis¹). For this reason, strength training is necessary to maintain muscle mass as you age. Also known as resistance training, this involves lifting weights, pulling against resistance bands, or using your own body weight in order to challenge your skeletal muscles.

Why is this important? Muscles are the drivers of your metabolism. Skeletal and cardiac muscles are covered with insulin receptors that soak up glucose for energy while you are working out. You need to activate these sugar sponges in order to keep your blood sugar down. Without sufficient muscle mass, where does the glucose from all the carbohydrates you eat go? You guessed it: it’s stored as fat, mostly around the waist – and mostly as triglycerides, the dangerous cholesterol. Without sufficient muscle mass, your pancreas must work harder to clear the glucose from your bloodstream. Conversely, even a brief workout such as a 10-minute walk after a high-carb meal will prevent a big spike in blood sugar.

Your intestines also depend on movement in order to maintain motility; rowing is especially good for moving digestion.

The importance of this chain of cause and effect can hardly be overstated: maintaining muscle mass is a major factor in preventing metabolic syndrome, a collection of markers of serious health conditions such as cardiovascular disease, diabetes, and stroke. Metabolic syndrome is defined as any of the following: elevated fasting blood sugar, elevated triglycerides, elevated blood pressure, or visceral (belly) fat (a waistline of 35 inches or more in women or 40 inches or more in men).

Sadly, fewer than 12% of Americans today are metabolically healthy. We are not exactly surrounded by positive role models. I encourage you to become one, and help turn the tide toward a healthier society. Exercise is a powerful tool for sculpting not only your figure but your metabolic profile.

Strengthen Your Skeleton

Strong muscles also bind and support joints. Provided you don’t overdo it and strain your connective tissue, weight lifting yields a definite feeling of being “shored up.” This reduces your chance of falling and breaking a bone or getting seriously injured. Sometimes I go to the gym three days in a row rather than spreading my visits out over the week. That’s when I really notice this feeling of binding strength. It’s a great feeling.

The same is true of exercise and bones: use them or lose them. Though we tend to think of bones as inert sticks that support our body like the wooden frame of a house, bones are dynamic and constantly changing. They are living mineral banks from which deposits and withdrawals are constantly made. Bones need to be tugged on by muscles in order to remain strong. Physical activity enhances the production of osteoblasts, which build bone cells. Osteoblasts are suppressed by cortisol, which is reduced by exercise. These are some of the reasons why weight-bearing exercise is crucial for maintaining bone mass. Mechanical loading also stimulates the production of collagen, which builds healthy bones as well as strong tendons and ligaments.

Regular exercise gives your bones and joints a reason to serve you. In times past, carrying water, chopping and lifting firewood, and a myriad of other physical tasks were an integral part of everyday life. Today we must be smart, and come up with more disciplined ways to keep our bodies strong. This is the price we pay for the many labor-saving conveniences in our modern lives.

Control Your Calcium Levels

Calcium metabolism is directly affected by exercise. During weight-bearing or resistance training, your osteoblasts signal your the body to deposit more calcium into the bone matrix. Muscle cells release calcium when they contract, and then reabsorb it in a cycle that becomes increasingly efficient with more turnover. Thus, exercise reduces the muscle’s need for calcium. If you experience muscle cramps in your legs at night, exercise is the answer.

Exercise also enhances the activation of vitamin D, which in turn enables calcium absorption and utilization.

Of course, it’s also necessary to ensure adequate calcium intake in your diet, and to prevent calcium loss from eating acidic foods. Calcium is alkaline, and will be pulled from your bones if necessary to neutralize too much acid. The most acidic foods are refined carbohydrates, processed foods, and alcohol (see my article “The pH Paradox” for more on this subject).

Integrating exercise with good nutrition is the key to maintaining a strong skeleton.

Help Your Heart

Movement increases circulation – not just by inducing your heart to work harder, but also by triggering the release of nitric oxide, a signaling molecule that expands blood vessels, enhances the activity of antioxidants, and lowers blood pressure. This benefits every system in your body, from your cerebral cortex to your thyroid, from your kidneys to your toes.

Movement naturally improves energy, and vigorous movement releases endorphins, those “feel-good” hormones that some athletes experience as a natural high. Think about that when you’re feeling the burn!

“Peak cardiovascular fitness . . . is perhaps the single most powerful marker for longevity.”
– Dr. Peter Attia, Outlive: The Science & Art of Longevity

How do you know your level of cardiovascular fitness? Some doctors offer a VO2max test, which measures your peak capacity for utilizing oxygen. Alternatively, try running on an elliptical treadmill that measures your output in terms of wattage. According to Dr. Attia, who is a champion of exercise, you should be able to bring your wattage up to at least twice your body weight in kilograms. For example, if you weigh 68kg (150lbs), you want to be able to sustain a running level of 140-150 watts for 15-20 minutes. As your weight drops, so will this target goal – a definite marker of improved cardiovascular fitness as your heart becomes less burdened to deliver oxygen to your entire body mass.

Boost Your Brain

Your brain is an organ in your body, and like every other organ, its well-being is directly affected by your diet and lifestyle. What benefits your body is good for your brain, and what hurts your health harms your brain. Exercise invigorates your cerebrovascular health, increasing circulation to every part of your brain. It enhances the activity of antioxidants in the food you eat, which neutralize free radicals in the endothelial lining of your cerebral blood vessels, and thereby reduces inflammation in your brain. A good cardiovascular workout protects the blood-brain barrier that shields your brain from pathogens and toxins, and stimulates the production of brain-derived neurotrophic factor (BDNF), which increases neuroplasticity and builds brain cells. Regular aerobic exercise therefore reduces the risk of neurodegenerative diseases such as Parkinson’s and Alzheimers. Higher levels of BDNF are also associated with a decrease in appetite.²

Your brain also needs mental exercise, which strengthens your ability to focus and think. Dr. Andrew Huberman points out that thoughts may be either reflexive or deliberate. Deliberate, focused learning and strategizing requires conscious awareness, and directly affects perception. Mental effort therefore constitutes exercise for the brain, and uses more energy than diffuse thinking or passive observation.³ Just by planning your workouts and getting yourself to the gym, the pool, the dance class, or the hiking trail, you are already exercising your brain!

“The latest science behind the magic of movement in protecting and preserving brain function is stunning.” – Dr. David Perlmutter, Grain Brain

Hone Your Hormones

Exercise increases testosterone, the get-up-and-go hormone that also boosts libido in both men and women. It increases your sensitivity to leptin, the hormone released by fat cells to signal satiety. Leptin’s hormonal counterpart, ghrelin, is produced by the stomach to stimulate hunger when it’s empty. Ghrelin is reduced by exercise, which in turn quells appetite. While the biochemistry of these hormones is not quite this simple, the general idea is that exercise reduces appetite and increases satiety. It makes sense: the point of food is to provide fuel – for metabolism, movement, and mental effort. The more you put the fuel to good use, the more efficiently it burns.

Nourish Your Nutrient-Sensing Pathways

Your body does not automatically absorb and make use of the food you eat. Instead, it uses nutrient-sensing pathways – biochemical “crosstalk” that allows systems in your body and individual cells to detect and respond to nutrient availability. These pathways govern energy usage and storage, regulate metabolism, and promote mitochondrial function and DNA repair. Nutrient-sensing pathways optimize metabolic flexibility and mitigate the risk of diabetes, cardiovascular disease, cancer, and neurodegenerative conditions.⁴ For these reasons and more, nutrient-sensing pathways play a significant role in determining longevity. This complex and fascinating subject is worthy of a whole separate article – but for now, all you need to know is this: every one of them is enhanced by exercise.

During intense exercise, one of these pathways, known as AMPK (adenosine monophosphate-activated protein kinase), even enables muscle cells to absorb glucose directly, without the need for insulin. This remarkable insulin-independent pathway also enhances post-exercise insulin sensitivity, making muscles more responsive to insulin for hours afterward. To learn more about the critical importance of insulin sensitivity to overall health and longevity, see my article “It’s All About Insulin.”

As if these benefits weren’t enough, exercise also offers other rewards: It increases lymphatic flow and induces DNA repair. Aerobic exercise in particular stimulates the creation of new mitochondria, your cellular energy factories, as well as mitophagy, the process that renews old mitochondria. It suppresses inflammation, improves insulin sensitivity, and reduces the glycation of proteins⁵ – the process by which proteins and sugars fuse together, causing connective tissue to stiffen and skin to wrinkle. And while a hard workout may cause a temporary rise in uric acid, this by-product of energy production is lowered in the long run by regular exercise. Conversely, a sedentary lifestyle is associated with elevated uric acid, which increases the incidence of not only gout but a whole host of metabolic disorders, including insulin resistance, obesity, and cancer.⁶

“Exercise is the key to unlocking the body’s regenerative and reparative systems.”
– Dr. Mark Hyman, Young Forever

Feel Your Food

Good energy and freedom of movement are the rewards of good nutrition. This is when you feel the effects of the foods you eat: all those colorful phytonutrients from fruits and vegetables, nuts and seeds, herbs and spices coursing through your bloodstream; all those proteins weaving into your muscle fibers; all those friendly fats fueling your cells; and all the toxins of our modern world pulsing out of you through your breathing and sweat. It is through exercise that the incremental benefits of good nutrition become palpable.

Best of all is the well-earned appetite that follows a good workout. These are the authentic cravings you can trust, for they speak from the depths of your body, letting you know your wellsprings need to be replenished with savory, nutrient-dense, mineral-rich food. By answering this call, you are building a bridge between your physical metabolism and your conscious awareness. It’s a gift to your future self – one that keeps paying forward in never-ending acts of nourishment and support.

The more you listen, the more your body speaks. And the more you give your muscles and bones a reason to serve you, the more they respond.

Be your own best friend, and think about that the next time you pick up weights, swim another lap, get on a treadmill, or use a rowing machine.

What is Optimal Exercise?

Health coaches divide exercise into four categories: cardiovascular or aerobic fitness; resistance, weight, or strength training; endurance; and flexibility. All are important and related, but the first two stand out as the most essential for optimizing nutrition, preventing disease and injury, and promoting cognitive health and longevity. Consistency is key, and yields the most rewards. You can find basic exercise guidelines for your age group here. For more detail, see Physical Activity Guidelines for Americans. Here’s a screenshot to get you started:

When it comes to long-term health, exercise and nutrition go hand in hand. That’s nature’s design. Movement literally gives your body a reason to live. There is a saying that “you can’t outrun a bad diet” – which is true: no amount of exercise will compensate for unhealthy or too much food. The opposite is also true: You can’t build a healthy body with diet alone, even if you eat all the right foods. You’ve got to move.

Now it’s time for me to take a break from writing and take my dog for a walk! I hope you will do the same, with or without a canine companion.

To your good health –

Yael Bernhard
Certified Integrative Health & Nutrition Coach

Yael Bernhard is a writer, illustrator, book designer and fine art painter with a lifelong passion for nutrition and herbal medicine. She was certified by Duke University as an Integrative Health Coach in 2021 and by Cornell University in Nutrition & Healthy Living in 2022. For information about private health coaching or nutrition programs for schools, please respond directly to this newsletter, or email dyaelbernhard@protonmail.com. Visit her online gallery of illustration, fine art, and children’s books here.

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1. https://pubmed.ncbi.nlm.nih.gov/15930468/

2. Perlmutter, David Dr., Grain Brain, Yellow Kite Books, 2018, pg 228.

3. https://www.hubermanlab.com/episode/essentials-how-your-nervous-system-works-changes

4. https://www.nature.com/articles/s12276-023-01006-z#

5. Perlmutter, David Dr., Grain Brain, Yellow Kite Books, 2018. Multiple references.

6. Perlmutter, David Dr., Drop Acid: The Surprising New Science of Uric Acid, Little, Brown, pp135-136.