Photo: Imani selemani Nsamila/Wikimedia Commons

The Hadza, sometimes called the Hadzabe, are a small Tanzanian group of indigenous hunter-gatherers. The Hadza have avoided attempts at colonization and westernization, which has allowed them to maintain a distinctive culture. Now, some nutritionists believe that the Hadza, who continue to forage for wild foods, might be healthier because of their resistance to adopting a modern diet. Proponents of the Hadza diet have argued that this way of eating can improve health by promoting a more diverse microbiome. Diverse microbiomes are beneficial because they have a greater variety of healthy microorganisms in the gut that can help digest food and maintain our overall wellbeing. 

The Hadza Diet: How it Works

A small population of the Hadza people still strictly adhere to a hunter-gatherer diet, meaning they don't eat any processed or farmed food. They eat what they can forage or hunt in the wild, including berries, root vegetables, honey and wild game. Their diet also changes with the seasons, depending on what kind of food is more plentiful. Research has found that the Hadza get about 100 grams of fiber per day, compared to Americans’ paltry average of 15.

“Eating a plant-based diet also alters the kind of bacteria that will be found inside your intestines,” said Laurie Endicott Thomas, MA, ELS, a nutrition and health author and editor. “As a result, there will be a correlation between the microbiome and overall health. The Hadza’s microbiome is a lot more “Western” during the dry season, when they eat a lot more meat.”

Researchers who published a study in Science found that the Hadza's gut microbiome changes with the season, which is important because it suggests people living in modern societies can diversify their gut microbiome by changing the way they eat. 

Unlike some popular diets that purport to be based on what all human ancestors ate, such as the paleo diet, the Hadza diet— for those of us in the West interested in its benefits —isn’t a highly restrictive eating plan. Instead, the goal is to eat as much like the Hadza as possible with the goal of improving the health of the gut and therefore boosting overall health.

What You Should Know About Your Gut Bacteria

Though most people think of bacteria as the reason for strep throat and abscessed teeth, most bacteria are harmless. In fact, many types of bacteria are beneficial, and our bodies depend on some to function normally. A complex colony of bacteria in the gut help the body digest and metabolize food. Mounting evidence, however, suggests that our modern way of life may undermine the function of these bacteria. 

This fascination with the gut microbiome is increasingly drawing the support of mainstream science. Researchers suspect that changes in the microbiome can affect virtually everything about health, including mental health. A handful of studies have even linked changes in gut bacteria to depression and anxiety.

Dr. Shawn Talbott, Ph.D., a nutritional biochemist who studies the microbiome, gut-brain-axis, and mental wellness, told CareDash that a diet rich in fruits and vegetables along with a probiotic and prebiotic supplementation regimen could improve gut microbiome diversity. 

“In general, ‘more diversity’ is better than ‘less diversity,’” said Dr. Talbott. “The best way to promote microbiome diversity is to eat a lot of high-fiber foods, like the Hadza do, on the order of 10x what a typical American might consume.”

Are the Hadza Healthier than Americans?

Researchers have proposed many reasons why the American gut microbiome might be impoverished compared to traditional societies. Maybe it’s overexposure to antibiotics. Perhaps excessive sanitation and antibacterial soaps are to blame. For now, we don’t know where the culprit hides. We do know that the Hadza and some other societies eat very differently than Americans. They’re also naturally lean, and they may have lower rates of chronic illnesses like cardiovascular disease and inflammatory disorders. 

One 2009 study compared gut bacteria of the average American to that of Yanomami people, an Amazonian hunter-gatherer community that has been extensively studied by western anthropologists. Researchers found 50% more bacterial diversity in the gut of Yanomami group members than in the gut of Americans. This statistic hints that something about modern lives might be depleting the microbiome of bacteria and other organisms that support human health. However, this diverse gut microbiome does not automatically point to healthier lives. 

"If you study the things that cause people to die before age 65, you can see that they fall into two basic categories: diseases of poverty and diseases of affluence," Thomas said. "Poor people die of starvation, injuries, parasites, infectious disease, and general lack of medical care. Rich people die from eating rich food. As a result, life expectancy is actually shorter for the Hazda than it is for us in the United States."

However, some research has linked fiber consumption to a longer life expectancy. So one option for improving health and improving the gut microbiome is to eat more fiber. For most healthy people, there’s no danger associated with significantly increasing fiber intake, though people with chronic constipation or bowel obstructions should talk to their doctor first. 

How to Follow the Hadza Diet

“The Hazda make their living by foraging,” Thomas said. “Thus, their diet is based heavily on a wide variety of plants, including many starchy tubers and roots. During the wet season, their diet is particularly high in carbohydrates (including berries and honey) and fiber and relatively low in fat and animal protein.”

Although you probably won't be able to commit fully to a hunter-gatherer lifestyle in 2017, one way to eat more like the Hadza is to boost your fiber intake. Fruits and vegetables are naturally high in fiber. Some of the best options include:

  • Avocados
  • Asian pears
  • Berries
  • Coconut
  • Figs
  • Artichokes
  • Peas
  • Okra
  • Acorn squash
  • Brussels sprouts

Some other simple strategies for eating more like the Hadza include:

  • Eliminating processed, packaged foods as much as possible. If it needs to be frozen, it’s not a healthy part of this diet.
  • Eating more fresh foods when they are ripe and in season. Pick seasonal fruits and vegetables as much as possible. Your local farmer’s market or community garden can be a great resource.
  • Eating more variety. Hunter-gatherers forage for many foods, allowing them to eat many different foods over the course of a year. Commit to trying new fruits and vegetables. An easy way to do this is to shop at local farmer’s markets and try a variety of grocers.
  • Cutting out as many refined carbohydrates — including sugary foods and white bread and pasta — as you can.
  • Eating smaller meals throughout the day, rather than sitting down for three big meals.

Most hunter-gatherer groups, including the Hadza, spend a significant portion of their day looking for food, walking and otherwise moving. So to get the most out of this diet, try to cultivate a more active lifestyle, too.

Does the Hadza Diet Work?

There’s little research available directly correlating the Hadza diet to a longer life in Americans. But the principles — eating more fruits and vegetables, reducing processed foods, eating different foods — are sound. A study that compared the gut microbiomes of Hadza to that of other tribal peoples and Americans found that the more a diet differed from a standard American diet, the richer it was in healthy bacteria. Merely abandoning meals of convenience in favor of fresh, seasonal food may offer a path to better health.

“Eating a low-fat, plant-based diet is good for your health,” said Thomas. “The China-Cornell-Oxford Project showed that adding even small amounts of animal-source food to the diet was associated with an increased risk of death from diseases of affluence. But for poor people like the Hazda, the use of animal foods during the dry season can prevent death from starvation.”

Even if the Hadza diet doesn’t improve health in people leading a western lifestyle, there’s little reason to suspect it might be unhealthy. As long as you get enough lean proteins from nuts, lentils, meat, and similar sources and eat sufficient calories, you shouldn’t expect any health issues.

Dr. Talbott says he wouldn’t necessarily recommend the Hadza diet, but he does suggest that people should consume a wide range of high-fiber fruits and vegetables as well as whole grains.

“Eating fewer processed foods and more “whole” foods has been associated with a wide range of health benefits and reduced risks for every modern disease including cancer, heart disease, obesity/diabetes, irritable bowel diseases, depression, and many more,” said Dr. Talbott. “We’re learning that many of these health benefits are mediated through interactions of the diet with microbiome, immune and inflammation pathways.”

However, Thomas added, it is difficult to know “how much (if any) of the health benefits of a plant-based diet are the result of the difference in the microbiome. We know that the microbiome is very important in ruminants, such as cattle. However, it may be far less important in monogastric animals, such as human beings.”

Who Should Try a Hadza Diet?

The Hadza diet doesn’t purport to cure any specific health problem. And while it’s not designed for weight loss, it often helps people lower the number of calories they consume. People with gastrointestinal issues may find it helpful, and those with metabolic concerns such as diabetes may learn that it helps them be more mindful of what they eat. 

If you are pregnant, nursing, planning to become pregnant, on a doctor-prescribed diet, or planning to put a child under 18 on the Hadza diet, talk to a doctor first.

The Hadza of today have changed and evolved as much as Americans, so seeing them as proxies for our ancestors is a mistake. Because they live so similarly to the way our ancestors did, however, they may be able to offer lessons about the nutritional environment in which we evolved. A diet that caters to those evolutionary needs might turn out to be better for our health than the packaged, processed, convenience diet most Americans eat.