Blue Zones and Bright Line Eating - the Healthiest Diets in the World?

I lived in Costa Rica for a few years a while ago and always seemed to feel much healthier when I was there. At the time I put it down mostly to the sunshine and the outdoor lifestyle. I would come back to England and struggle with the weather, put on weight, and start getting headaches and other issues. I carried on travelling to various parts of Latin America and within a few days of getting there I always started feeling a lot better.

It was only in recent years that I started to understand why my diet would have had a lot to do with it. Living in England my weight had crept up to what was for me an uncomfortable 11 stone in spite of good gym programmes, yoga, trying various diets – none of which worked – and getting exercise with my dogs and horse.

I’ve been fascinated to discover that the Nicoya Peninsula in Costa Rica is one of the five “Blue Zones” in the world that are longevity hotspots. An unusually high proportion of inhabitants in the Blue Zones live healthily into their 80s and 90s, even 100s, remaining active and largely avoiding the sort of chronic diseases that usually accompany old age. The other Blue Zones are the Barbagia region of Sardinia, Italy; Ikaria, Greece; Okinawa, Japan; and Loma Linda, California (an Adventist community who are mostly vegetarian or pescatarian).

Dan Buettner, author of Blue Zones Kitchen argues that although other factors contribute (such as community, lifestyle, spirituality and purpose), the secret of the Blue Zones starts with food choices. He has analysed more than 150 dietary studies conducted in the Blue Zones over the past century and distilled the findings into these common denominators:

· Food is “whole food”. In all of the Blue Zones, people traditionally eat the whole food. Ingredients may be raw, cooked, lightly ground or fermented, but never highly processed. Dishes typically contain half a dozen or so ingredients, simply blended together. Around 90% of the food is grown within ten miles of the home, and food preparation is simple. People living in the Blue Zones therefore hardly ever ingest any artificial preservatives. The foods they eat, especially the grains, are digested slowly and don’t cause blood sugar to spike.

· Food is mostly plant-based. In the Blue Zones roughly 95% of food comes from a plant or plant product. Favoured foods are beans, yams, sweet potatoes, fruit, nuts, seeds, whole grains and greens (especially the very healthy, leafy greens – spinach, kale, beet, chard and collards). People often grow their own garden vegetables and fruit or have someone to buy them from very locally, and preserve them to use during the off-season. If meat is eaten it is only in very small quantities, or for an occasional celebration. Plant-based oils especially olive oil are preferred to animal-based fats. Seasonal fruits and vegetables, whole grains and beans dominate Blue Zone diets.

· Meat is consumed rarely. When meat consumption is averaged out over the Blue Zones, it is found that people only eat very small amounts of meat, about two ounces or less at a time, about five times per month. About once a month they might eat more at one time, at a celebration for example. The animals are usually family-farmed and free-roaming, and industrial, processed meats not eaten. Interestingly, Buettner says “We’re not sure if people lived longer because they ate a little bit of meat as part of the Blue Zones diet or if they thrived despite it. There are so many healthy practices Blue Zones people engaged in, they may have been able to get away with a little meat now and then because its deleterious effect was counterbalanced by other food and lifestyle choices”.

· Fish is eaten often. People living in the Blue Zones tend to eat fish on average two or three times a week, and some eat a small portion daily, as a common part of everyday meals. In most cases the fish being eaten are smaller, inexpensive fish such as anchovies, sardines, trout and cod that are sustainably caught by local fishermen. They don’t eat farmed fish such as farmed salmon or commercially caught fish such as tuna that involve more ethical issues (such as overfishing) or health issues (such as bioaccumulation of pesticides and PCBs).

· Minimal consumption of cows’ milk and dairy products such as cheese, cream and butter. Cows’ milk does not feature significantly in any Blue Zones diet except that of some of the vegetarian Adventists in Loma Linda who eat dairy products and eggs. Only goats’ and sheeps’ milk products – especially full-fat, naturally fermented yoghurt with no added sugars – appear in the diets of both the Ikarian and Sardinian Blue Zones.

· An occasional egg. Eggs are eaten in all five Blue Zones diets, where people eat them an average of two to four times a week. However eggs in the Blue Zones come from chickens that tend to roam freely, eat a wide variety of natural foods, are not given hormones and antibiotics, and lay slowly maturing, smaller eggs that are naturally higher in omega-3 fatty acids. Commercially produced eggs generally come to maturity about twice as fast as eggs laid by Blue Zones’ chickens.

· Beans are eaten daily. Beans are fundamental to all five Blue Zones diets: black beans in Nicoya; lentils, garbanzo and white beans in the Mediterranean; soya beans in Okinawa. People in the Blue Zones eat at least four times as many beans as people in the west on average, providing most of the daily vitamins and minerals they need. When I lived in Costa Rica, I was surprised at first to find that every local meal seemed to involve rice and black beans! The typical meals were “gallo pinto” for breakfast (rice and black beans with egg), a “casado” for lunch (a big meal of rice, black beans, salad, fried plantain and chicken/fish/meat), and something else with rice and black beans for dinner! Beans contain more nutrients per gram than any other food, and are packed full of protein, complex carbohydrates and fibre.

· Minimal added sugar. Blue Zones diets have naturally occurring sugars in fruits and vegetables, but very little added sugar. They may eat some sweets during celebrations, but their foods have no added sugar and they typically sweeten their tea with honey, which all adds up to about seven teaspoons of sugar a day on average. In Blue Zones diets, people consume about the same amount of naturally occurring sugars as an average American, but only about a fifth as much added sugar (an average American consumes about 22 teaspoons).

· Nuts are eaten daily. People in the Blue Zones eat about two ounces (about a handful) of nuts daily: almonds in Ikaria and Sardinia; pistachios in Nicoya; and all types of nuts in Loma Linda. Studies have shown that diets with nuts reduce “bad” LDL cholesterol, regardless of the amount of nuts consumed or the fat level in them. Nuts are a useful source of fibre, vitamin E, vitamin B complex, magnesium, selenium, copper, arginine and antioxidants. Eating nuts may help prevent metabolic syndrome and type 2 diabetes. Nuts have strong anti-inflammatory properties.

· The only drinks consumed regularly are water, tea (mainly herbal teas), coffee and wine. With very few exceptions, people in the Blue Zones drink only these beverages. Fizzy drinks and other sugar-laden or artificially sweetened drinks are unknown to most Blue Zone centenarians.

· Bread is whole grain or sourdough. Some bread is eaten at most meals in three of the five Blue Zones. However, breads in Ikaria and Sardinia are made from 100% whole grains including wheat, rye and barley, and grains are often ground at home. Whole grains have higher levels of fibre than most wheat flours commonly used in commercial bread-making, and are much richer in nutrients including tryptophan, selenium and magnesium. According to Buettner, barley was the food most highly correlated with longevity in Sardinia. Other traditional breads in the Blue Zones are sourdoughs, made with a “starter” of naturally occurring lactobacilli bacteria, which digest the starches and glutens while making the bread rise. Traditional sourdoughs such as those consumed in the Blue Zones have very little gluten and may actually lower the glycemic load of the meals they are consumed with. However many commercially-made sourdoughs may not be made using an authentic sourdough starter and therefore may not have the same nutritional properties.

In the 1970s, David Davies of the Gerontological Unit of University College, London, and author of Centenarians of the Andes travelled to remote areas of southern Ecuador, verifying stories of people living to great ages, some up to 140 years or more, while at the same time remaining lucid and agile. Ages were in most cases successfully verified from church records. He found that the centenarians were people living in households that tended their own land on homesteads far from the nearest towns and villages. They continued to work on the land into old age and had a significantly different diet from people in the villages. They also used a large range of local plants and herbs for medicine.

Davies explains “Nearly all centenarians are closely involved with the land in their lives and the bulk of their food is grown in the locality…The oldest inhabitants were in fact those living outside the villages, and thus living a different life, and eating very different food, healthier in content, and lower in calories. As we know, diet and health are closely connected, and thus the significance of these mountain smallholdings and their way of life, unaffected by the towns and town food, is something we take very seriously.”

The diet of these mountain people consisted of yucca (cassava), maize (eaten as sweetcorn or corn on the cob), beans including soya beans, green vegetables, cabbage, marrows, pumpkins, potatoes, fruit, cottage cheese made from cows’ or goats’ milk, eggs and very rarely meat. In comparison, writes Davies, “The village people’s diet was based on pasta, white flour, white sugar and tinned foods – all much less good for the health than the more austere mountain diet – and the villagers looked and were, much less healthy. Many of these foods were introduced from the towns…The remarkable fact about the health of the centenarians is that they hardly suffer at all from killer diseases such as cancer, heart disease and diabetes, and yet in nearby areas and towns these diseases are common.”

Interestingly, in the 1970s Davies also investigated the coast of Norfolk as a longevity pocket of note in the UK. He wrote of people living to a great age there, “These people do not have a very easy life, especially in winter. Again, the majority for the greater part of their lives obtained most of their food from their large gardens, and from the locality. They thought a possible cause of their great ages was living mainly upon fresh fruit and vegetables”. He also mentions that most of the people living to a great age in the UK had had livelihoods associated with a lack of wealth and would not have been able to afford rich food – “plain food was the order of the day”.

It was when I discovered Bright Line Eating in 2019 that I found my own personal path to weight loss and healthy eating. By that time I felt like I’d tried everything else and the principles of Bright Line Eating made perfect sense. I weighed 11 stone in June 2019 and by the end of November 2019 weighed 9 stone 3lbs. I had loads more energy, my blood sugar was balanced, I felt so much more comfortable and also stopped getting migraines. Bright Line Eating has most of the features of a Blue Zones diet (I wasn’t aware of Blue Zones diets when I started doing it) with one main difference: no flour, even “healthy” flours such as barley flour, chickpea flour, whole-grain wheat flour, oat flour or spelt are allowed. The whole grains or plants are certainly allowed, just not the flours, and no added sugars either. Flours and sugars (other than sugars eaten in whole foods such as fruit and vegetables) are broken down and enter the bloodstream too fast.

As Susan Peirce Thompson explains in her book Bright Line Eating, “Just as with sugar, the Bright Line for flour is ALL flour. It’s not about the type of plant. It’s not about gluten. It’s about surface area. When the grain is processed, ground down to make flour, the surface area of each particle gets multiplied exponentially. This is true for whole-grain flour too. When the surface area is increased, our digestive enzymes have a field day accessing the glucose and it hits the system too fast and too hard. My friend, Dr Alan Christianson, gave me a great analogy for this. He said he thinks about the digestive process as akin to melting ice. Eating a whole-grain food, like brown rice, for example, is like taking a huge square block of ice and leaving it on a driveway to melt. It will, but slowly, over the course of many hours. Eating brown rice flour, in contrast, is like sprinkling ice shavings all over a hot black driveway. They melt on contact. Sugar and flour affect the body in slightly different ways, which is why it’s important to give them up in tandem. Sugar primarily breaks down into glucose and fructose. Flour breaks down into just glucose. Fructose can only be processed by the liver, which is why we’re seeing such high incidence of fatty liver disease in our culture. Flour hits all the cells. Think about that. A full-body assault”.

Bright Line Eating also has some other guidelines to do with portion sizes, sticking to meal times and planning ahead. At first I thought it would be incredibly difficult to do, as so much of my diet at that point included flour and sugar (and when I had first heard of Bright Line Eating a few years earlier I had completely discounted it thinking it would be impossible for me to do!) But I felt so much better and saw the results so quickly, and there was so much I could still eat and enjoy, it actually became easy and enjoyable. I felt good like I had done in Costa Rica when unbeknown to me I had been eating mainly a Blue Zones diet, with minimal bread and pasta and very little added sugar.

A lot of people who come across Bright Line Eating struggle to understand why “healthy” flours and sugars aren’t allowed. They mention their grandparents and great-grandparents who seemed to live healthily eating bread and other flour-based goods as a staple part of their diet. They think it must be modern wheat flours, with their genetic modification, pesticide use, higher gluten levels, greater processing and additives that are the problem. However Susan Pierce Thompson, the founder of Bright Line Eating, argues that our predecessors, if they were healthy, were generally eating much less bread (and flour) and as part of an otherwise much healthier wholefood diet, so it didn’t adversely affect them so much. Whereas today, most of us have been exposed to large amounts of highly processed flours and sugars in our diets from an early age, as a much higher proportion of our diet. As a result, many of us have physical ill effects and damage from the flour and sugar that we need to heal from, as well as problems of psychological addiction to them. She gives a brilliant explanation in this video, “What happened to flour?” Her video about “healthy” sugars is also very interesting:

In his book The Fall about the changes in humans that started about 6,000 years ago, Steve Taylor mentions the research and archaeological evidence that shows that when our ancestors developed farming, and societies became dependent on grains and flours, we became less healthy. He writes: “Research has shown that – strange though it may sound – the diet of hunter-gatherers may actually have been better than many of ours in the modern world. Apart from the small amount of meat they ate (10 to 20 per cent of their diet) their diet was practically identical to that of a modern-day vegan, with no dairy products and a wide variety of fruits, vegetables, roots and nuts, all eaten raw (which nutrition experts tell us tell us is the healthiest way to eat). This partly explains why most of the skeletons of ancient hunter-gatherers which have been discovered have been surprisingly large and robust, and show few signs of degenerative diseases and tooth decay…Studies by the physiologist Jared Diamond have shown that the hunter-gatherers of Greece and Turkey had an average height of five feet ten inches for men and five feet six inches for women. But after the advent of agriculture, these declined to five feet three and five feet one respectively… The ancient hunter-gatherers were less vulnerable to disease than later peoples. In fact, until the advances of medicine and hygiene during the nineteenth and twentieth centuries, they may well have been less afflicted with disease than any other human beings in history”.

He goes on to explain, “The hunter-gatherers had eaten a wide variety of foods but now (with agriculture) people’s diet was usually centred around two or three different types of grain, which meant a lack of nutrition and dietary balance. As a result, as Christopher Ryan puts it, ‘Throughout the world, the shift to agriculture was generally accompanied by a dramatic drop in the quality of people’s diets severe enough to leave tell-tale signs on their bones which can still be read by paleopathologists.’”

I’m currently trying to work out how far a Blue Zones diet or a Bright Line Eating diet can be adapted to be fully vegan and still be properly healthy. I’m also looking into how far the principles can be applied to canine and equine nutrition. I’m already a fan of raw-feeding and healthy, omnivorous diets for dogs and avoiding processed feeds for horses. It will be very interesting to see if these diets become mainstream in the next few years. I’m sure our health, and that of our pets, would benefit greatly.




Dan Buettner, “The Blue Zones Kitchen: 100 Recipes to Live to 100”,

David Davies, “The Centenarians of the Andes”

Susan Peirce Thompson, PhD, “Bright Line Eating: The Science of Living Happy, Thin and Free”

Steve Taylor, “The Fall: The Insanity of the Ego in Human History and the Dawning of a New Era”

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