Potential Risks to Skipping Breakfast

By Carly Smith, BS, MPH(c) 

Potential Risks to Skipping Breakfast

Many people know the saying, “Breakfast is the most important meal of the day” yet fasting until noon (one type of intermittent fasting) has become popular and mainstream. While it may be beneficial for some, Stanford Lifestyle Medicine physicians and researchers caution new fasters and want to highlight some important considerations for those thinking about skipping breakfast.

“Limiting the time frame that calories are consumed has become a popular dietary strategy to improve health and aid in weight management. Fasting until noon is one of these popular strategies,” says Jonathan Bonnet, MD, MPH Stanford Lifestyle Medicine Physician. “For some, this may work well, however, the preponderance of evidence suggests that weight loss is modest and no more beneficial than overall caloric restriction.”

Side Effects of Skipping Breakfast

Delaying the first meal of the day until noon falls into the category of time-restricted eating. Although this eating pattern may help someone reduce their overall caloric intake, it may also lead to disruptive changes to their circadian rhythm, which could negatively affect sleep, as well as insulin sensitivity and glucose uptake.

In a recent review, researchers discussed the potential impacts of skipping morning-time breakfast. The review reported associations between skipping breakfast and an increased risk of developing obesity or type 2 diabetes. These studies primarily focused on the short-term effects of introducing the morning fasting behavior into one’s routine, however, the long-term effects of habitually fasting until noon are still being studied.

Feeding the Circadian Rhythm

Eating breakfast early in the morning is one signal that influences the genetic pathways underlying the circadian oscillations in the gut, which are critical for predicting daily energy levels and jump-starting metabolism. Thus, skipping breakfast could weaken the signaling of these clock genes and could be one reason why some people that fast until noon experience higher hunger levels throughout the day.

 “Skipping breakfast impacts numerous circadian signals within the body that may be suboptimal,” says Dr. Bonnet. “If someone wanted to try a time-restricted approach, they may experience more benefits from having an earlier eating window (to include a more substantial breakfast) with limited late-night food consumption.”

While research is still trying to understand how impactful these circadian changes are long-term, it is possible that irregular or inadequate fueling of the body may negatively affect one’s body weight, glucose metabolism, and overall health. Thus, it may be more beneficial for one’s health to prioritize consistently eating meals at the same time every day.

“From a circadian perspective, regularity is key,” says Jamie Zeitzer, PhD, Stanford University Professor and member of the Stanford Lifestyle Medicine Sleep team. “The circadian system anticipates signals, like food intake, at certain times of the day and synchronizes gut activity in response.”

Not All Fasting is Bad

Fasting until noon is just one type of eating pattern and not all types of fasting have negative health effects. There are other forms of intermittent fasting that are currently being studied in longevity science due to their ability to build resilience to stress and diseases. For individuals facing obesity and related chronic diseases, time-restricted eating approaches (that maintain the morning fasting window), have not been shown to be significantly more beneficial for weight loss than those following overall caloric restriction methods.

“For those with weight-related cardiometabolic conditions like Type 2 Diabetes, most forms of weight loss can improve their condition,” says Dr. Bonnet. “Finding a way to create a sustainable caloric deficit to lose weight is a challenge, so if some variant of intermittent fasting works for them, it may be the key to start improving their overall health.”

Anyone considering any form of intermittent fasting or time-restricted eating should consult with their physician to make sure that it is the healthiest decision for them both physically and mentally.


The Impact of the Western Diet on Diverticulitis

By Maya Shetty, BS

Recognizing the vital connection between colorectal health and diet has never been more important, given the escalating prevalence of colorectal diseases in Western societies. According to Cindy Kin, MD, MS, a colorectal surgeon at Stanford, many of these conditions are preventable and are linked to the dietary patterns we develop early in life.

“Many people in the US have a chronically low fiber diet high in inflammatory foods beginning in childhood that leads to microbiome dysbiosis, as well as actual structural changes to the gastrointestinal tract,” says Dr. Kin. “Over time, this leads to numerous colorectal diseases, some of which are irreversible and require surgery.” 

One specific condition that has seen a significant increase in prevalence in the last 50 years is diverticulosis, characterized by the formation of irreversible outpouchings in the colon. This condition affects approximately one in three individuals aged 50-59 and virtually everyone over the age of 90 in the US.

Diverticulosis itself does not cause symptoms, and most patients only find out about them when they have a colonoscopy. However, anyone with these diverticular outpouchings is at risk of developing diverticulitis, a painful disease triggered by perforations in one or more diverticula. Diverticulitis may range in severity from mild to severe and life-threatening, depending on the size of the perforation. A tiny pinhole perforation that seals itself quickly might cause a little pain and inflammation that can be treated with oral antibiotics. On the other end of the spectrum, a larger perforation that leaks air and stool into the surrounding abdominal cavity can make someone so sick that they would need to have emergency surgery.  

“Three to five million people get some sort of treatment for diverticulitis per year in the US,” says Dr. Kin, “A proportion of those people need surgery, making diverticulitis one of the most common reasons for colon surgery.”

The Growing Prevalence of Diverticulitis in the US

Diverticulosis became a known problem in the US in the early 1900s, coinciding with major technological advancements, such as fertilizers, preservatives, and factory farming. These advancements caused significant changes in the American diet. Regular consumption of high-fiber, farm-fresh whole foods was replaced by processed foods lacking in essential nutrients. Diets also became increasingly saturated with meats, fats, and sugars, replacing fruits, vegetables, and whole grains. As our diets followed this trend and became more “Westernized,” cases of diverticulitis significantly increased. 

This US-specific increase in diverticulitis is in stark contrast to the nearly negligible incidence found in regions of the world where diets are rich in fiber. In Asian countries, where the diet is becoming more influenced by Western culture, we observe a rising incidence of diverticulitis in the last 30 years. “Diverticulitis is almost entirely a disease of our Westernized diet, low in fiber and high in ultra-processed foods and saturated fat,” says Dr. Kin.

What to Eat (and Not to Eat) to Reduce the Risk of Diverticulitis



Dietary fiber, found in various forms in vegetables, legumes, and whole grains play a critical role in maintaining soft, easily eliminable stool. Conversely, diets lacking in fiber often lead to hard smaller-caliber stools and constipation, prompting the colon to work extra hard to move it through. Years of  sustained high pressure within the colon is thought to be the root cause of diverticulosis, the presence of outpouchings in the wall of the colon. These outpouchings, or diverticula, form as the colon is squeezing so hard that it pushes out a portion of its own wall. The diverticula are weaker than the rest of the colon wall, and are more prone to bleeding and perforations. Research has consistently demonstrated that diets rich in fiber are strongly associated with a reduced risk of developing diverticular disease.

For many years, the widespread recommendation for those with diverticular disease was to avoid nuts, seeds, and popcorn due to the perceived risk of these foods getting trapped in the diverticular outpouchings. However, research suggests this is not the case and eating these foods may actually reduce one’s risk of developing diverticular disease due to their fiber content. “In all my years operating on diverticulitis, I have never seen a popcorn kernel or a sunflower seed poking out of a diverticulum causing a perforation, yet patients continue to steer clear of these fiber-rich foods due to this persistent diet myth,” says Dr. Kin.

Dr. Kin’s recommended daily fiber intake for women is 30-35 grams and 35-40 grams for men. While there are numerous fiber supplements available to help reach this daily goal, Dr. Kin recommends getting your fiber from dietary sources because foods that naturally contain fiber offer a multitude of advantages that extend beyond digestive health, such as lowering cholesterol and weight management to lower the risk of heart disease, stroke, diabetes, and other chronic diseases.

“If your body is not used to a high-fiber diet, gradually add fiber into your daily meals to allow your body to adjust over a couple weeks,” cautions Dr. Kin. “For most people, the gassiness that can happen with eating more fiber will get better pretty quickly, so don’t give up! A little gas upfront for a lifetime of colon health is a small price to pay.”

Processed Foods

Processed foods often lack the essential dietary fiber that whole unprocessed foods naturally provide. Additionally, the overconsumption of refined sugars and saturated fats in processed foods has been associated with several adverse health effects, including changes in gut microbiota composition and an increased risk of inflammation within the gastrointestinal tract. These factors can further exacerbate the risk of diverticular disease development.

Red Meats

Diets high in red meat are linked to diverticulitis, with a large-scale study finding the risk increasing by 18 percent for every additional serving of processed red meat. Red meat is associated with inflammation within several internal organs, and excessive consumption over time has numerous health consequences, including deteriorating colorectal health.

To prevent diverticulitis and several other colorectal diseases, Dr. Kin highly recommends “adopting a whole food, plant-based diet for its exceptional combination of high fiber content and nutrient-dense antioxidant  properties.”


In a Pickle? Unveiling Gut-Friendly Pickles for Your Health

By Maya Shetty, BS

By now, most people have heard about the extensive health benefits fermented foods provide. Fermented foods have become increasingly popular as research continues to reveal that their high concentration of probiotics can improve gut health, boost immunity, and enhance digestion.

“Pickles are fun, tangy, potentially health-promoting ways of eating cucumbers,” according to Dr. Marily Oppezzo, PhD, MS, Head of the Lifestyle Medicine Nutrition Pillar.

However, Dr. Oppezzo cautions that even though the beloved snack of pickles are thought to be fermented, not all of them are, hence, they don’t all have the health benefits. 

Determining whether a particular pickle brand is fermented or not can pose a challenge. In this blog, we will delve into the various pickle varieties, offer guidance on spotting fermented options at grocery stores, and highlight recommended brands to seek out.

How to Choose a Healthy Pickle?

Dr. Oppezzo says that all pickles are a healthy snack, whether they are found on the shelf of the grocery store or in the refrigerated section. However, if you’re looking for a pickle to support gut health, you’ll have to select from the pickles in the refrigerated aisle.

“The pickles that are beneficial for your gut health are the fermented ones, made by brining them in salt rather than vinegar,” says Dr. Oppezzo. “While vinegar pickling is a common method, true fermentation in brine enriches them with beneficial probiotics for your gut. How can you spot these live bacteria-packed pickles? Check out the refrigerated section of your grocery store, as they won’t be found on the regular shelf.”

As Dr. Oppezzo mentioned, pickles essentially fall into just two primary categories: pickled pickles and fermented pickles.

  • Pickled pickles (aka vinegar pickled) are produced using, as you might have already guessed, vinegar. The vinegar kills all bacteria, including the bacteria beneficial to one’s gut. This process effectively sterilizes the pickles and allows them to shelf-stable. Therefore, these pickles are found unrefrigerated in the grocery store.
  • Fermented pickles are produced using brine and go through a natural fermentation process involving bacteria that is inherent within cucumbers. These pickles contain beneficial bacteria for the gut known as probiotics, as long as they have not undergone pasteurization. The pasteurization process, which involves heat, effectively eradicates probiotics from pickles.

So, what you want to look for are unpasteurized fermented pickles, which can be found in the refrigerated section of grocery stores, often in the cheese section. It is always good to double-check the label as well. If vinegar or pasteurized is indicated on the label, chances are probiotics are absent. Instead, look for these terms on the label: “fermented,” “unpasteurized,” , “live cultures”, and/or “probiotic”. Another sign that pickles are naturally fermented are the presence of bubbles on the surface of the brining liquid – a by-product of live bacteria at work.

Dr. Oppezzo also recommends prospective buyers to “spend some time reading labels and look for ‘added sugar’ on the label to be sure you aren’t accidentally getting sugar through your pickles.”

Why are Fermented Pickles Healthier?

Probiotics Support the Microbiome

Fermented foods have a variety of health benefits due to their high concentration of probiotics, 

or beneficial microorganisms aka the “good” bacteria. The microbiome within one’s gut helps to digest food, absorb nutrients, synthesize vitamins, and regulate one’s immune system. Research consistently demonstrates that healthy, stable microbiomes that are high in diversity and beneficial microbes  are shown to reduce chronic inflammation, weight gain, and disease.

Nutritional Benefits

Fermented pickles offer a range of nutritional benefits due to the diverse array of compounds they contain. These include antioxidants like flavonoids and phenols, which fight inflammation and protect cells from oxidative stress. The pickling process may also enhance the bioavailability of these antioxidants. Additionally, pickles contain a high concentration of vitamins and minerals, specifically vitamin K, vitamin C, vitamin A, calcium, and potassium. 

Immune Benefits

Vegetables that undergo the fermentation process typically produce natural substances such as alkyl catechols. Alkyl catechols activate a defense pathway that shields against various chronic diseases linked to oxidative stress. These substances may also boost the activity of cell defense pathways that protect our body from cancer and neurodegeneration.

Be Careful of the Sodium!

Despite all these potential health benefits, pickles are not the perfect snack.

“One major downside of pickles is their high salt content,” Dr. Oppezzo cautions. “A single pickle can contain over two-thirds of the recommended daily sodium intake for an average adult. Excessive sodium can be detrimental to overall health, thus it is important to eat pickles in moderation. If you are going to have them and are watching your salt, eat after you’ve sweat a lot due to exercise or a sauna.”


What Should Athletes Eat to Fuel Peak Performance?

Athletes, driven by the pursuit of peak performance, have been in the spotlight for numerous studies exploring how various dietary patterns optimize performance. Due to the breadth of research and recommendations available, athletes are at a crossroads when determining the best way to fuel their goals. For this reason, our Stanford Lifestyle Medicine team members (Matt Kaufman, MD, Maya Shetty, BS, Michael Fredericson, MD, and Marily Oppezzo, PhD) reviewed the research regarding how popular diets impact athletic performance and well-being. They summarized their findings in a comprehensive research article titled Popular Dietary Trends’ Impact on Athletic Performance: A Critical Analysis Review, which was recently published in the journal Nutrients. Their research focused on six dietary patterns: Mediterranean diet, ketogenic diet, low-carbohydrate diet, plant-based diet, intermittent fasting, and disordered eating. Whether you are an elite athlete or an enthusiastic beginner, keep reading to learn more.

Mediterranean Diet

The Mediterranean diet, rich in whole grains, unsaturated fats, lean proteins, fruits, and vegetables, is consistently associated with improved health and performance for athletes. Research on athletes finds this diet is linked to improved muscle power and endurance, as well as body composition. The low inflammatory index of this diet is also associated with enhanced recovery time.

Ketogenic Diet

The ketogenic diet restricts the consumption of carbohydrates and protein to boost the use of fat as an energy source, thus improving weight loss and potentially athletic performance. While this may help athletes, such as wrestlers, who need to stay within specific weight requirements, the prolonged carbohydrate restriction can negatively affect training performance. Research has shown this restriction can increase baseline heart rates, perceived exertion, and rate of bone loss, harming short and long-term performance. However, research has not found significant decrements in performance for athletes following this diet.

Low-Carbohydrate Diet

People often think that Ketogenic and Low-Carbohydrate diets are the same. A low-carbohydrate diet is less restrictive and does not restrict protein intake in the same way that Ketogenic diets would. Research has found that athletes on this diet have no differences in muscle strength and power compared to athletes following a regular diet. However, notable improvements in sprint times and exhaustion perceptions have been observed. As carbohydrates are restricted, the same detriments on performance found in ketogenic diet research may occur. Studies examining low-carbohydrate diets use extremely variable interventions that are difficult to compare. Thus, more research is needed to determine its specific impact on performance.

Plant-Based Diet

Plant-based diets are also adopted by many athletes due to ethical or health-conscious reasons. This choice is supported by the literature, which suggests that vegetarian and vegan athletes perform just as well in terms of endurance and strength as their omnivorous counterparts. Following a plant-based diet can have numerous health benefits. Plant-based protein sources, such as tofu, lentils, and beans, have been found to improve circulation, reduce inflammation, lower oxidative stress, promote a healthy gut microbiome, enhance glycogen stores, and support leaner body weights.

However, due to the restrictions of these dietary patterns, following them without proper planning may lead to nutritional deficiencies, such as protein, vitamins B12 and D, iron, zinc, calcium, total calories, and iodine. These deficiencies may affect performance, recovery, and bone health. Despite the risk of these deficiencies, staying attentive to one’s nutritional needs and working with a sports dietician can help you to either take the right supplements or plan a plant-based diet that meets all your needs.

Dr. Matthew Kaufman, the lead author of the review paper, states, “Because plant-based diets are high in carbohydrates, low in fat, and rich in vitamins, minerals, and antioxidants, they can provide important nutrients an athlete needs for performance. In order to maximize a plant-based diet for training and competition, athletes may want to consult with a sports dietitian to ensure adequate nutrient intake and to get well-balanced examples of nutritionally fulfilling meals.”

Intermittent Fasting

Intermittent fasting, with its varying protocols, involves limiting the time window for eating during the day. This dietary pattern might not be suitable for athletes given their training schedules or the nutrition to fuel performance. As a result, the potential risks may outweigh the benefits. Limited eating windows may be helpful for weight loss or maintaining a strict weight class, but it can also lead to low energy availability and actually harm performance and overall health. Research studies have found that intermittent fasting impaired athletes’ sprint speed and endurance.

Disordered Eating

The pressure to maintain a low body weight for athletics can lead to restrictive diets or even clinical eating disorders, affecting both physical and mental health. These include anorexia nervosa, bulimia nervosa, binge eating disorder, and orthorexia. Athletes, especially those in aesthetics-focused sports such as gymnastics, dance, and ice skating, have the highest rates of disordered eating and eating disorders. These eating patterns can weaken muscles, cause fatigue, and lead to injuries and complications like anemia and osteoporosis. Restrictive diets like ketogenic, plant-based, or intermittent fasting might appeal to athletes with disordered eating tendencies. Thus, athletes should carefully assess their motivations for diet changes and consult professionals to ensure their nutritional needs are met.


To summarize, the researchers found that the Mediterranean diet has the most benefits for athletes regarding recovery and performance. Low-carbohydrate and ketogenic diets show no harm to athletic performance; however, the non-ketogenic low-carbohydrate diets that emphasize protein intake might be more sustainable for the energy demands of athletics. Vegans and vegetarians are at high risk for nutrient deficiencies, especially in nutrients essential for athletic recovery and muscle maintenance. Intermittent fasting may aid weight loss but could hamper athletic performance in endurance and aerobic sports.  For any dietary intervention, the reasoning for the change should be closely monitored by the athlete and their healthcare team to ensure disordered eating is not a risk. Restricting the type and amount of food an athlete consumes can severely impact performance and overall well-being.

Dr. Matthew Kaufman, the lead author of this review article, emphasizes, “Nutrition and athletic performance are inextricably linked. The Mediterranean diet is abundant in foods that support the high energy demands of athletes and promote recovery. However, no one diet is universally recommended for athletes, and any dietary changes should be done in collaboration with healthcare professionals to ensure maintenance of overall health.”


By Maya Shetty, BS


  1. Kaufman M, Nguyen C, Shetty M, Oppezzo M, Barrack M, Fredericson M. Popular Dietary Trends’ Impact on Athletic Performance: A Critical Analysis Review. Nutrients. 2023 Aug 9;15(16):3511. doi: 10.3390/nu15163511. PMID: 37630702; PMCID: PMC10460072.
Fasting May Benefit Our Gut Health

High Fiber Fermented Foods – The One-Two Punch Boost for Your Gut and Immune Health

Having a diverse microbiome is good for you, but how can we increase diversity in our digestive system through what we eat?

A 2021 study from Stanford University suggests that diets high in fiber and fermented foods might be just the ticket to increasing diversity in your microbiome and could even strengthen your immune system.

You may have heard of the concept of one’s microbiome—the diverse community of bacteria, fungi, viruses, and other microbes that live on our skin and inside of our bodies. The health and balance of our microbiome is critical to our own health. In healthy bodies, our microbiota helps us digest our food, stimulate our immune system, and provide us with other benefits. Each person’s microbiome is unique, with our first exposures to these microorganisms coming from our mothers during birth and through breastmilk and later affected by our environments, diets, and lifestyles [1].

The study followed two groups of participants, each prescribed to increase either their fiber or fermented foods consumption over a 17-week period. Participants in the fermented foods group saw increased microbial diversity at the end of the study period and decreased inflammatory markers. Inflammation correlates with a host of chronic diseases, so learning that we can decrease it while increasing our microbial diversity makes fermented foods a one-two punch. Participants in the high fiber group were observed to have increased capacity for digesting fiber, suggesting increased numbers of beneficial microorganisms but no significant increase in diversity [2]. Eating foods that are high in fiber AND fermented, such as sauerkraut or kimchi have the possibility of having all three benefits, increasing the diversity and number of beneficial microorganisms as well as decreasing inflammation.

In studies of immigrants to the United States, observed “westernization” of their microbiota has been correlated with loss of microbial diversity and functionality along with deteriorating health indicators such as weight gain and increased inflammation [3]. A healthy body goes hand in hand with a healthy microbiome. Why not try integrating high fiber fermented foods to give your body a boost?

By: HannahZoe Chua-Reyes, BS


  1. National Institute of Environmental Health Sciences
  2. Gut-microbiota-targeted diets modulate human immune status
  3. U.S. immigration westernizes the human gut microbiome
How Does Caffeine Affect You?

How Does Caffeine Affect You?

It is difficult to predict how and for how long caffeine affects our bodies. Research suggests that caffeine affects everyone differently and our relationship with it could change as we age. A study examining the relationship between chronotype and the effects of caffeine on sleep in Stanford students found early birds had a strong correlation between daytime caffeine use and waking during sleep. Night owls’ sleep seemed to not be affected by their daytime caffeine intake. People in between seemed to experience minor effects. However, this study was exclusive to Stanford students, who are generally a more sleep-deprived population. It is unclear the degree to which this affected the results but is likely a significant confounding variable.

One of our sleep experts, Dr. Jaime Zeitzer, PhD, says , “There is massive variability in how people metabolize caffeine and in many, even a single cup of coffee with breakfast can interfere with sleep. Being aware of how your caffeine consumption personally impacts your sleep is incredibly important.”

By: Carly Mae Smith, BS

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  1. Modeling caffeine concentrations with the Stanford Caffeine Questionnaire: preliminary evidence for an interaction of chronotype with the effects of caffeine on sleep
Coffee & Longer Lives

Coffee & Longer Lives

A team here at Stanford studying inflammation in older adults found an interesting correlation between those that regularly drank caffeinated coffee and those with lower levels of chronic inflammation. The study suggests that regular, moderate coffee intake may protect us from age-related inflammation and diseases. The clinical trial looking at markers of inflammation and age-related diseases found that 89 older subjects who regularly consumed caffeine from coffee experienced suppressed disease-related inflammation.

Before grabbing your next cup of joe, there are a few things are team would like you to keep in mind:

1) Coffee can mask grogginess, but you still need regular, sustained sleep! Coffee at any time of the day could disrupt sleep.

2) Too much sugar in your coffee may negate Some health benefits!

3) Be careful not to drink too much! Caffeine levels vary by coffee type.

4) If you don’t like coffee, try tea! We see many nutritional benefits in black and green tea too!

There are lots of factors to consider when discussing the impact of coffee and caffeine on our lifestyles, and we hope to cover a lot of them in the near future! To learn more about how caffeine may affect people differently, check out our post on caffeine and chronotypes.

By: Carly Mae Smith, BS


  1. Expression of specific inflammasome gene modules stratifies older individuals into two extreme clinical and immunological states
Beneficial Effects of Tea on Longevity

Beneficial Effects of Tea on Longevity

The study analyzed data from 6387 participants and identified three distinct tea consumption trajectories. After a median follow-up of 17.9 years, it was found that high tea consumption was associated with a lower risk of mortality, but this effect was observed only in non-alcohol drinkers. Among current alcohol drinkers, increasing tea consumption was linearly associated with increased mortality. Additionally, the study revealed that alcohol intake masked the protective effect of tea consumption against blood pressure progression.

In conclusion, individuals with a long-term high tea consumption trajectory had a lower risk of all-cause mortality and a slower rate of blood pressure increase. However, the beneficial effects of tea consumption were diminished or even harmful in the presence of alcohol intake.

By: Michael Fredericson, MD

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  1. Alcohol intake masked the protective effects of tea consumption against all-cause mortality and blood pressure progression: Findings from CHNS cohort, 1993–2011