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Your Breakfast is a Metabolic Disaster

Updated: May 30

How an American invention became a metabolic nightmare, and what I eat instead

By Austin Perlmutter, MD



  1. Origins of Modern Cereal: John Harvey Kellogg, a doctor in the early 1900s, believed bland foods contributed to wellness and developed the first corn flakes cereals. Contrary to his brother William, who added sugar to cereals for commercial success, John aimed to reduce people's sex drive and avoided adding sugar.

  2. Rise of Sugary Cereals: In the 1940s and 1950s, sugar became a central ingredient in cereals, driven by the convenience for the post-WWII generation and effective marketing. This led to cereals becoming a staple breakfast food in America despite their high sugar content.

  3. Misleading Health Claims: Breakfast cereals are often marketed as healthy, but a study showed that 92% of cold cereals in the US have added sugars, with some popular brands being over 50% sugar. These cereals primarily consist of refined carbohydrates that quickly turn into sugar upon digestion.

  4. Nutritional Aspect and Alternatives: Breakfast cereals are typically fortified with vitamins and minerals but lack essential nutrients. Healthier breakfast alternatives should include real, minimally processed foods rich in fiber, protein, and healthy fats, such as legumes, nuts, seeds, leafy greens, and proteins like salmon and eggs.


What did you eat for breakfast this morning and why? If you’re like most people, breakfast was a mix of refined carbohydrates and added sugars, a combination that’s doing your overall and brain health no favors. Common examples of unhealthy sugary/simple-carbohydrate breakfasts include Danishes, muffins, bagels, pancakes, and waffles. Added sugars are in particular linked to negative health effects ranging from higher risk for diabetes, obesity, liver disease as well as worsened brain function. Combining added sugar with highly processed carbohydrates may have additionally negative impacts on metabolic state.  


But there’s one unhealthy breakfast that beats out all the rest when it comes to popularity. Every day, around 50% of Americans begin their day with a bowl of cold cereal. Why is it such a poor choice for health, how have we been duped into choosing this ultraprocessed junk, and what are the better options? Read on!


Breakfast cereal is a metabolic nightmare. So how did it get so popular?

Modern cereal gets its start early in the 1900’s with a doctor named John Harvey Kellogg. Kellogg had some rather peculiar beliefs about health. In particular, he believed that bland foods were the secret to wellness, an opinion that undergirded the subsequent development of the first corn flakes cereals. He even proposed that eating bland cereal would help decrease people’s sex drive, something he viewed as a major benefit. However, his belief in the healing power of bland also meant keeping added sugar out of his original cereal formulations.


Unlike John, his brother William Kellogg was less concerned about keeping things plain and more concerned about selling cereal. So, despite John’s concerns, William and the nascent Kellogg’s company started adding sugar to their cereal. And here’s where things go south, metabolically speaking. Over the next decades copious amounts of added sugar became the name of the game in cereal manufacture. By the 1940’s and 1950’s, sugar was inseparable from cereal. This, coupled with the incredible convenience of cold cereal for a post-WWII baby-boom generation (along with highly successful marketing campaigns) were central to this junk food becoming America’s breakfast staple.


Cereal companies then (and now) marketed their products as a “healthy” way to start the day. But the reality is that most breakfast cereal is simply a vehicle for sugar. In 2014 the Environmental Working Group explored the sugar content of over 1,500 types of cereal, and the results were shocking. An incredible 92% of cold cereals in the US had added sugars. Some of the most popular cereals were over 50% sugar! A Canadian study reached another astonishing conclusion, reporting that of 262 sampled cereals, sugar was the second most common ingredient. As a reminder, in addition to the sugar, the most common ingredients in cereals are refined carbohydrates that rapidly convert into sugar when we digest them.

But wait, isn’t cereal “part of a complete breakfast?”

One of the most common marketing lines for breakfast cereal concerns its place as “part of a complete breakfast.” This famous line of copy has been touted for decades, but what does it tell us? The hidden truth is simple: cereal doesn’t provide the necessary nutrients you for health, so you need to be sure to eat real food along with it.


What about the fiber and vitamins and minerals?

One of the easiest covers for the cereal industry relates to the vitamins and minerals found in most common breakfast cereals. These cereals are called “fortified,” which means they’ve had vitamins and minerals added to them after processing. Basically, this is supplementation in the form of food. It’s not a bad idea if we’re deficient, but if we’re eating real food for breakfast (see the list below), there’s far less need to eat these ultraprocessed foods. If you do choose to eat breakfast cereal, look for those with low sugar content (ideally, less than 5g per serving), high fiber (at least 3-5 grams per serving), and a composition that’s made only of a few ingredients

If cold cereal is a poor choice for breakfast (and it usually is), what should we do instead?

A “complete” breakfast would (from my perspective) consist entirely of real, minimally processed foods that prioritize elements like fiber, protein and healthy fat. Some of favorite and incidentally excellent sources of each include:


  • Legumes (I love black beans with my breakfast)

  • Nuts and seeds (almonds, walnuts, chia seeds and sunflower seeds are some of my top choices)

  • Leafy and dark greens (kale, collard greens and broccolini pair great with savory breakfast items)

  • Avocados: Yes! These fruits are actually a great source of fiber!

  • Coffee: a large cup may contain several grams of fiber



  • Salmon and mackerel and tuna (though watch the mercury on the tuna!)

  • Eggs (a daily go-to for me)

  • Beans, seeds, nuts and nut butters

  • Protein powder (if you’re in a hurry, and a great option if you’re plant-based)

  • Chicken, turkey and other poultry

  • Greek yogurt (get the unsweetened versions)


Healthy fats

  • Olive oil (I can’t go without it)

  • Nut and seeds, hemp hearts (yet again)

  • Salmon and mackerel

What do I actually eat for breakfast? Some personal favorites:

  • Black organic coffee

  • Egg scramble with veggies and avocado and olive oil

  • Chia seed bowl with coconut milk and nuts and fruit on top

  • Black beans with over easy eggs and olive oil

  • Greek yogurt with nut butter, chia seeds and hemp hearts

  • Plant-based protein shake with added creatine monohydrate (post-gym)

  • High protein/low carbohydrate pancakes (almond flour is a great option)

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Thanks so much for this really clear information - I am 73 and had a Quantum Magnetic Analyser reading - from a Health Kinesiologist - a few months ago, which registered - memory slightly fading, blood sugar (urine) towards pre-diabetic, a hypoxic lack of oxygen in cells, + a loss of calcium - a wake up call ! She suggested a good vitamin and mineral supplement as she finds that when these get back into balance things improve - and this is happening. Your information about fibre versus carbs was extremely useful - as I was unclear about this. Thanks also for your excellent recent docuseries - I have given up sugar and made my exercise timetable better - Yoga…

Replying to

Thanks Sheila!


Hi Dr. Perlmutter in the blue zone of Costa Rica, they eat gallo pinto for breakfast, that is rice and beans with onions, bell pepper and cilantro with garlic in a small amount, sometimes with eggs or cheese or and a tortilla with black coffee. What do you think?

Replying to

When I stayed with a family in Monteverde that was what I had every morning. So delicious! There's a lot to be said about specifics of diets in different parts of the world. I think diet matters a lot but is far from the only variable that affects brain health outcomes. My experience in CR was that everyone had far more active lives and was far more immersed in community. Also, that local black coffee can't hurt :)


Kevin Oliveira
Kevin Oliveira
Dec 23, 2023

Hi Doc. Perlmutter, I'd like thank you for all information you've given in your newsletter through email as well. It's really helpful and it has made difference in my life since I started read your posts. I appreciate it.

Kevin from São Paulo, Brazil.

Replying to

This is such a kind comment. Thanks Kevin!

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