10 gut health

No, I’m not talking about intuition. I’m talking about the health of the bacteria that live in our intestines, metabolize our food, and so much more. Why? you ask. Well, you can follow all the steps I’ve laid out for you to nourish your body properly, but if you don’t consider your gut health, you’re missing a key piece of the puzzle.

Our microbiome, which is the population of bacteria (microbiota) in our gut, is thought to influence everything from our mood to our immunity. Seventy to 80 percent of our immune system is in our gut.1 The microbiota also help digest food, especially carbohydrates, break down toxins and medications, control inflammation, and may impact how our genes express themselves (the delivery of information from DNA to the genes to create molecules like proteins). This is important because the way a gene is expressed can affect our health and our risk for disease, although we aren’t yet sure exactly how our gut bacteria does this.

There is also some discussion about whether our microbiome has an effect on our weight, and we suspect that it does in some way. Many believe that we metabolize food and absorb calories differently according to our gut-bacteria profiles. However, that’s basically all we know: We’re not at the point where you can switch up your gut bacteria to optimize weight loss. All you can do is make sure that your little gut bugs are happy; this is the best way to improve your overall health.

Sleep and stress go hand in hand with gut health. Not only are they absolutely linked to what we choose to eat, as we’ve touched on earlier, but they also affect how we metabolize our food. Gut health, sleep, and stress are like the icing on the nourishing diet cake—they’re not everything, but they finish it all off and are definitely an important ingredient. In fact, few things impact our nutrition and health like our guts, sleep patterns, and stress levels. In this chapter, I’m going to walk you through the integral role all three play on our health so you can function at your very best.

Let’s start with our gut.

WHAT IS OUR GUT?

Our gut—otherwise known as our intestinal tract, is home to one of the largest colonies of bacteria in our body: our microbiome. The microbiome is even considered by some to be another organ in our bodies and the total weight of it can be up to 2 kg.2 That’s almost five pounds of bacteria. Yeah, the thought of that makes me squirm, too.

Each of us has our own gut microbiota profile. While we share the same 1,000 gut-bacteria species, your profile will be different than everyone else’s, thanks to what you eat, how you live, and where you live. People in different parts of the world have vastly different gut microbiota, tailored to digesting the host’s native diet.3,4

So, how do these little guys work?

Think of your gut as a fermenting tank. When we eat food that contains fermentable fiber—otherwise known as prebiotics—such as the fiber in legumes, oats, fruits, root vegetables, and nuts, it travels to our large intestine, where it’s broken down and fermented by our gut bacteria.5 This process nourishes the bacteria while producing short-chain fatty acids (SCFAs) called butyrate, proprionate, and acetate, which help provide energy to cells in the colon, balance blood sugar, reduce inflammation, protect the colonic cells, and may even destroy cancer cells in the colon.6 All good stuff!

But if we eat a diet that’s very high in protein and low in fiber, that fermentation process results in different compounds that can swing the microbiome balance in favor of pathogenic bacteria, which are damaging to our health.7 This may cause inflammation and a higher risk for conditions such as colon cancer, inflammatory bowel disease, diabetes, and even fatty liver. The consumption of a diet high in fiber can control this effect. In other words, fiber is our gut’s best friend.

While eating fiber goes a long way to ensuring good gut health, a less-than-ideal diet, stress, travel, illness, and antibiotics, among other things, can cause dysbiosis, which is when there is an imbalance in your gut bacteria—either there has been a die-off of good bacteria, an overgrowth of pathogenic bacteria, or a loss of diversity overall. The repercussions are not fun. Symptoms can include diarrhea, bloating, gas, and constipation. Dysbiosis can affect your immune system, making you more susceptible to pathogens and infection. It’s also implicated in conditions such as obesity, inflammatory bowel disease, and allergies; whether dysbiosis is a cause or an effect of these conditions we don’t know, as microbiome research is in its infancy.8 Still, it’s widely accepted that keeping our microbiome healthy and diverse is important for our health. And diet, sleep, and stress all play a huge role in that.

Let’s start with how what we eat affects our gut.

PREBIOTICS AND PROBIOTICS

When I talk about nutrition and gut health, prebiotics and probiotics are usually one of the first things people want to know about. As we discussed above, prebiotics are the fiber that feeds your gut bacteria. Probiotics are the actual good bacteria that live in your gut. The official definition of a probiotic is live microorganisms that, when taken in adequate amounts, confer a health benefit on the host.9 In other words, when you eat enough probiotics, you’re populating your gut with more of the good guys.

The plant-forward eating habits that you’ve learned so far in this book are already gut-friendly, but there are other good-for-the-gut foods you can add to your diet. Some prebiotic-rich foods are:

Probiotic foods include fermented options such as:

But not all of these contain the right bugs, in the right amounts, every time we eat them. This is one of the challenges of probiotic foods.

For example, most of us have heard that yogurt is a good source of probiotics. My mother used to force yogurt on me whenever I took antibiotics as a kid, which was a lot! In reality, not every yogurt is probiotic. Some have probiotics, but those don’t survive their trip through the stomach to the intestine, where they ferment. And even if they do, recent research shows that the levels in the product are often too low to have any effect.11 While some yogurts claim to help fight colds, lower cholesterol, decrease cavities, and improve IBS symptoms, the above study found that you’d have to eat up to twenty-five servings of some yogurts to get these effects. Thanks, but no thanks. I’d rather just live with my cold. Yogurt and other products can also be full of sugar, which negates the point of eating them for their probiotics, in my opinion.

There are also different strains of probiotics that do different things in different amounts, which is important if you’re selecting a probiotic for a specific issue—like bloating or diarrhea, or just for general health. But when it comes to food, we just don’t know the amount and strains of probiotics that these foods contain, and it’s not enough to have the vague claim of probiotics on the label. It’s all fine to claim that your tortilla chips have probiotics in them, but which probiotic bacteria do they contain and how much? Are they going to make it past your stomach acid? That information is probably not available, and it’s all too common for people to be swayed by the claim without having all the necessary facts. In truth, there’s no real evidence that foods that have added probiotics in them (hello, probiotic chocolate) have any positive effects on our health.

Fermented foods like kimchi and sauerkraut don’t have a probiotic claim on their labels, and sometimes they’re not even labeled: The Polish deli near my brother’s house has a barrel of sauerkraut in the back, which is how it’s sold. That stuff is probably probiotic AF, but nobody will ever know for sure. Other fermented foods that naturally contain probiotics are kefir, tempeh, miso, and kombucha (watch the sugar content in this!).

There’s no harm in adding probiotic foods to your diet, and I think that fermented foods, as opposed to foods that have added probiotics are your best bet. Remember, though, that the organisms in the product need to be live to be considered probiotic.12 Look for products that say “naturally fermented” and contain bubbles in the jar, which indicate the presence of live bacteria. Don’t cook them, since heat will destroy their good bacteria.

If you need a probiotic, supplements are the best way to get the right amounts and strains, though the research is mixed. Some studies suggest that certain probiotics may reduce frequency and duration of the common cold and help alleviate IBS symptoms, but many are conflictive or inconclusive, or don’t have solid methodology.13,14 Some people do find probiotics helpful, especially for conditions that have positive research behind their use—mostly antibiotic-induced diarrhea and C-difficile. However, in most cases, we don’t know how much of which probiotic to take to effectively treat different ailments.

That being said, probiotic supplements are generally safe, so if you have gut issues and want to try them, ask your pharmacist for their recommendations. Here are a few things to remember.

While the FDA has not approved any probiotic to treat illness, some companies have taken the time to do thorough research on their product. I feel like in the future we’ll each have a prescribed personal probiotic strain that matches our microbiome. Unfortunately, the science to do that isn’t there yet. In the meantime, talk to your pharmacist for a recommendation to get the best product for your concerns.

myth buster:

gut-bacteria test kits.

You can now get gut-bacteria test kits that come with diet and nutrition advice tailored to your personal microbiome. While this sounds very forward-thinking, the common consensus from the scientific community (and myself) is that the science isn’t there yet. We can get our microbiome read, but we don’t know what to do with that information, especially when it comes to making recommendations for weight loss. Since there’s no value in getting information that we don’t know how to interpret yet, I’d pass on these tests for now.

SLEEP PATTERNS

When I sit down with clients for the first time, I ask them all sorts of questions that don’t seem to pertain to nutrition, like how they’re sleeping and if they have a stressful life. They sort of look at me funny, like “I thought this was about nutrition?” and then I explain that things like sleep and stress are absolutely linked to our diets and our gut health.

Sleep and nutrition are a two-way street. Lack of sleep affects our food choices, but our food choices can also affect the quality of our sleep.15

My mom used to tell me that I wouldn’t grow if I didn’t sleep. Nice scare tactic, Mom! But she was partly correct: Sleep influences the release of growth hormones. It also impacts glucose tolerance and plays into the release of cortisol, leptin, and ghrelin, all hormones that you’re familiar with by now.16 Studies suggest that sleep debt increases insulin resistance as well as levels of ghrelin and cortisol, and decreases leptin—and this is likely in part why lack of sleep has been linked to obesity.17 When your leptin is low and your ghrelin is high, it’s tough to stop eating. It’s just science.

Sleep deprivation also affects our endocannabinoid system (ECS). Unlike the cannabinoids in marijuana, endocannabinoids are lipid-based neurotransmitters made by your body that help to regulate appetite, among other functions. While research on the ECS is just ramping up—it was discovered in the 1990s—early studies indicate that inadequate sleep may increase the amount of endocannabinoids in your blood, and thus a desire to eat.18 This is what happens when you smoke or consume marijuana and get the “munchies,” except in that case, cannabinoids, not endocannabinoids, are to blame.

Beyond these chemical reactions taking place in your body, sleep deprivation also causes physical exhaustion, which means you may not have the energy or desire to be active or to prepare your own meals. You may also gravitate toward comfort foods to sort of “cocoon” yourself in to make yourself feel better. Being on a diet that’s too low in carbs or very high in refined carbs may also cause sleep disturbance.19

Sometimes, getting enough sleep and dialing down the stress in our lives is harder than it looks. As a parent, I know how aggravating it can be to hear how we need eight hours of sleep a day, that sleep heals everything, and that sleep deprivation is detrimental to health. When my kids were really young and kept me up all night, I wanted to throw my computer against the wall every time I saw some celebrity pontificating about the importance of getting your beauty sleep. I wanted to sleep more than you could ever imagine, but I couldn’t control my kids waking me up in the middle of the night. Any of you parents know exactly what I’m talking about. The average adult gets around seven hours of sleep a night, but clearly, they didn’t survey new parents, or insomniacs, for this figure.

Being up all night with kids is one thing, but many of us are sleep deprived by choice. Meaning, we don’t prioritize sleep like we should. Instead, we sit on our smartphones all night, binge-watch Netflix into the wee hours, or work into the early hours. In our busy, hectic lives, sleep often gets shoved onto the back burner. We think we’ll make up our sleep debt on the weekend or when we’re on vacation, but face it, that rarely happens. When it does, it’s never enough. We’re just too busy, and we can’t shut our brains off.

By this point in the book you know that my MO is: Do your best. It’s also: Don’t try to control everything. And that applies to sleep, too. You might not be able to control your kid waking you up in the middle of the night, but you can definitely try to improve your sleep through your habits and your diet.

For some of us, going to bed at a reasonable time and getting a solid night’s sleep is pretty much impossible, at least consistently. Whatever the cause, try to optimize your time in bed as much as you can. If you know you’re probably going to be woken up in the middle of the night, try to hit the sack a bit earlier to front-load your sleep. Leave the dishes and the laundry, and get your ass to bed. You know the drill:

These small habitual changes will improve what’s called your sleep hygiene. But it’s also important that you eat for sleep. Read on.

MELATONIN

Melatonin is a neurohormone our brains make that regulates sleep, but it can also be found in some foods, which when eaten before bedtime can help you fall asleep faster. Melatonin-rich foods include: tart cherries, bananas, pineapples, almonds, walnuts, and oats.20,21 You can also take melatonin supplements, but as I always say, try to get what you need from food first.

TRYPTOPHAN

This is an amino acid found in dairy, meats, and seeds. Maybe you’ve heard that turkey and milk make us tired because they contain tryptophan. Tryptophan is a precursor to melatonin, meaning our bodies use tryptophan to produce melatonin. It’s also used to make serotonin, famously known for being the neurotransmitter that relaxes us.22

When we eat tryptophan-rich foods, their tryptophan is converted in the brain to the compound 5-HTP (5-hydroxytryptophan), then to serotonin, then to melatonin. This doesn’t mean you should take serotonin supplements. It’s all about the tryptophan, which can cross the blood-brain barrier, unlike serotonin. And while 5-HTP supplements exist, the evidence that they aid in sleep is inconclusive. There is no official dosage of 5-HTP for sleep, and the quality of supplements can vary. Most importantly, 5-HTP taken in conjunction with some other medications—especially SSRIs—can be lethal.

MAGNESIUM

Magnesium is an element that helps our bodies maintain nerve and muscle function, keeps bones strong, and supports our immune system.23 It also increases GABA (gamma aminobutyric acid), a neurotransmitter that helps us relax. In other words, it’s good for sleep and our guts.

However, a high percentage of U.S. adults don’t get the recommended 320–420 mg of magnesium in their daily diets.24 People with GI conditions that cause chronic diarrhea and malabsorption such as Crohn’s disease or celiac disease; alcoholics; people with type 2 diabetes; people with a low-magnesium diet, and older adults are all at risk for magnesium deficiency.

The good news is that magnesium is readily available in our food. The best food sources are almonds, cashews, peanuts and peanut butter, spinach, black beans, edamame, and whole wheat bread.

There are also magnesium supplements that you can take before bedtime to help with sleep. Choose one that dissolves in water for maximum absorbency. Magnesium citrate is a good option that’s commonly used in sleep-promoting magnesium supplements. Remember that magnesium is also a laxative (hence milk of magnesia), so take it according to package directions.

ALCOHOL

Booze might be good at putting you into a deep sleep. Alcohol increases our production of adenosine, which is a compound that induces sleep. That’s good enough to make you tired and get you into bed, but that’s not the end of the story, sleepwise.

When you have more than one drink, your brain shows a lot of delta activity, or slow-wave sleep. This is deep restful sleep that you’ll experience for the first half of the night. That’s all good, except that after we drink, alpha activity, which normally happens when you’re relaxed but not asleep, steps in later on. The alpha and delta activity together inhibit deep sleep, making you feel unrested when you wake up.

Alcohol also tends to reduce REM sleep, the sleep stage in which you dream.25 It’s the most restorative sleep stage, which again explains why you feel like you didn’t even sleep when you wake up after a night of drinking.

And ever wonder why after you drink, you’re up at the crack of dawn? That’s because by that time, your body has had the chance to metabolize the booze you guzzled the night before and the sleep-promoting chemical adenosine that got you into bed in the first place has now worn off. Worst feeling ever.

STRESS LEVELS

Stress and sleep are related, and so are stress and nutrition. Stress affects our ability to sleep, which can lead to overeating. But it can also affect the balance of our gut bacteria.26,27,28

As we talked about before, the type and diversity of the bacteria in our gut can directly affect our health. Even though research on how stress affects gut bacteria is still in its early stages, there are studies that suggest that prolonged stress can affect intestinal permeability, which may lead to inflammation in our body. This may be why when we’re stressed, we’re more prone to flare-ups of IBS and other conditions.

Stress affects the chemistry of our bodies and it all leads back to cortisol. Remember the flight or fight response we discussed in the carb chapter? Here’s a reminder. When we’re stressed, our body needs more energy to fight the perceived threat, so it releases cortisol, which increases our appetite and suppresses our insulin production.29 Insulin helps control the amount of sugar in the blood, but our body wants that sugar for energy. As if that isn’t enough, elevated cortisol levels also tell our body to release triglycerides for energy, which can cause high triglyceride levels in the blood. In cases of chronic stress, the fight-or-flight instinct is constant, resulting in increased hunger, weight gain, and a buildup of sugar and triglycerides in the blood, which may lead to type 2 diabetes and elevated risk of heart disease.

We’re not done with cortisol yet, that naughty monkey. High levels of cortisol suppress our immune system, leaving us susceptible to illness. That feeling of being run-down when you’re burning the candle at both ends? It’s a real thing. Cortisol also compromises our GI system in order to save energy. But when digestion slows, we experience bloating, constipation, and eventually malabsorption and inflammation. It makes you wonder how many people with IBS symptoms are suffering from chronic stress! But if you have IBS or IBD, you might also notice that stress triggers your symptoms and flare-ups. That’s because of cortisol.

In terms of food choices, when we’re stressing about something, sometimes we feel like we need crunchy, fatty, or sugary foods to ease our mood. It goes back to emotional eating. When we’re stressed or unhappy we tend to choose foods that transport us back to simpler, happier times. This can mean your favorite childhood birthday dessert or whatever food you associate with being stress-free and content. It can also mean that when we’re angry or stressed, we crave crunchy food because we want to kick the shit out of something. Make sense?

But that’s not the only reason we crave comfort foods when we’re stressed. Recent research suggests that in some people, eating sugary, fatty foods in response to stress may decrease the body’s hypothalmic pituitary adrenal axis stress response in the long-term.30, 31 Meaning, people who chronically self-medicate their stress with food may actually be decreasing all that cortisol and hormone secretion. Unfortunately, the other side of the coin is greater abdominal obesity, which is detrimental to health.

Certain diets also cause us more stress. Hell, dieting itself causes stress! When you’re constantly worried about what you can and can’t eat, how much you weigh, and whether you’re going to feel obligated to share a platter of chicken wings with your workmates on Thirsty Thursday, that shit gets stressful. And if you happen to be cutting carbs, things get even worse because very low-carb diets (10 percent of calories or less) are associated with elevated levels of cortisol, so without adequate carbs, your body is in a state of low-level stress.32 All. The. Time. That can’t be healthy, right? Yeah, it’s not.

Okay, so now that I’ve thoroughly exhausted you, here are some things you can do:

If you have a lot of stress that you can’t reduce with lifestyle changes, you should be eating foods that reduce inflammation. High-value eating is already anti-inflammatory: it contains lots of whole foods, fruits and vegetables, whole grains, and less sugar and ultraprocessed items. Avoiding trans and high levels of saturated fats is also important for keeping inflammation at bay. Caffeinated beverages such as coffee have been known to increase stress levels, so avoid adding insult to injury by cutting down caffeine when you’re overly stressed.

There are a lot of articles online that tout the cortisol-reducing powers of B and C vitamins, but the truth is that research either doesn’t support or is conflicted about these theories. While magnesium might be good for sleep, there are no studies that encourage its use in cortisol reduction. Some research suggests using DHA to lower cortisol, but the studies are low quality and the results aren’t convincing.

Interestingly, what does appear to lower cortisol levels in humans is ashwangandha, an adaptogen that’s derived from a plant in the nightshade family (flowering plants like tomatoes, eggplant, and peppers).33, 34 If you decide to take an ashwangandha supplement, consult your pharmacist to cross-reference it with any other medications you may be taking. Ashwangandha is known to interact with thyroid medications, steroids, and sedatives, among others.

You may never have guessed how much our gut, sleep patterns, and stress levels ripple out to affect our diet. But keeping them all in check and optimizing them to the best of your ability can have a profound effect on your mood, food, and overall wellness.

If you follow the high-value eating plan, prioritize your right to rest, and say no to some of the stuff that makes your life crazy, you’ll be naturally helping your gut, sleep, and stress levels. Those are the key ingredients in a recipe for success.