In his new Netflix documentary series Down To Earth, Zac Efron, actor and producer, traveled to different parts of the world to explore healthy, sustainable ways to live with wellness expert Darin Olien. In the fourth episode, he makes a trip to Sardinia, Italy, which has the highest number of people that live to be 100 per capita. This area is called a “Blue Zone” for having a high concentration of centurions, and it is one of the five blue zones on the planet. National Geographic says these areas have the “world’s healthiest people.” Their secret to a longer life? It’s a mixture of things, but the one that stands out the most is their diet, which does include a steady amount of carbs.
Throughout the episode, Efron learns the ways of the Sardinian people and gets a taste of their low protein, high-carb diet. The Sardinians focus on natural foods within their meals, which do include lots of vegetables and fruits as well. But the amount of protein consumed looks vastly different compared to the American diet, which shocks Efron after he spent many months focusing on a high-protein, low-carb diet for a previous acting role in Baywatch.
Both Efron and Olien were shocked by the scientific studies around the Sardinian people and concluded that it was a way of life they wished to adopt. While a stress-free life in the quintessential village of Sardinia eating homemade pasta on the regular does sound ideal, we had to ask ourselves: Is there scientific evidence to back up these claims about a high-carb diet?
We did some research around the topic and also spoke with five registered dietitians to understand the bigger picture behind the lifestyle of the “world’s healthiest people.”
There are risks to having a high-protein diet.
Toward the beginning of the episode, Efron and Olien met up with two researchers in Sardinia and talked about the risks of a high-protein diet. One of the risks mentioned (which shocked Efron greatly) was how a high intake of animal protein can actually promote age-related diseases, like heart disease and cancer.
Studies show that animal protein (particularly red meat) has a high level of methionine, which is related to the aging process through your metabolism. According to Healthline, amino acids (such as methionine) are essential for building the proteins that make the tissues and organs of your body and contribute to normal cell function in the body. While this is a good protein to have in your diet, having too much of it can have some dangerous side-effects.
This, of course, is very different compared to the high-protein lifestyle that is regularly recommended across American culture. So we asked the experts.
“As a general rule Americans overeat protein, we are hyper-focused on getting it in and don’t have a good handle on what appropriate portions are,” says Vanessa Rissetto MS, RD, CDN and co-founder of Culina Health. “People who overeat protein might forget other macronutrients like carbs and sometimes fat which may omit whole grains, vegetables, and fruit which are loaded with fiber, minerals, and micronutrients necessary to bodily function and helping to decrease the proliferation of free radicals which lead to cancer.”
“Yes, you can over-consume protein and have health consequences,” says Toby Smithson, MS, RDN, LD, CDCES, FAND, Diabetes Lifestyle Expert, author of Diabetes Meal Planning and Nutrition for Dummies and founder of DiabetesEveryDay.com. “Interestingly, when you do the math, these centenarians in Sardinia are following the protein requirements we have in our recommended daily allowance guidelines for good health. Consuming too much protein can promote weight gain because the excess protein will be stored as fat.”
Smithson says the recommended dietary allowance (RDA) of protein intake should only be 20% of your daily calories. Consuming a lot more than that can create numerous risks including issues with constipation, diarrhea, dehydration, heart disease, calcium loss, and cancer risk.
“We need to be cautious of overloading our kidneys by eating too much animal protein, especially if you have diabetes and are at higher risk for chronic kidney disease,” says Smithson. “Studies have shown that high dietary acid load increases the progression of End-Stage Renal Disease in adults with Chronic Kidney Disease and increases the risk of developing type 2 diabetes.”
The Sardinians don’t indulge, they simply eat in proper portions.
However, protein is clearly still an important part of the diet, and studies show that not properly nourishing your body with it can also be harmful to longevity and metabolic health. The important thing is to know the proper portions.
“The bigger risk is probably not eating enough protein as protein is vital for so many processes in the body,” says Amy Goodson, MS, RD, CSSD, LD. “There are lots of health benefits to getting protein including building and maintaining lean muscle mass, which supports strength and balance as we age. The key is choosing lean, high-quality protein and distributing it over the course of the day to help with muscle resynthesis and satiety.”
Goodson says it’s important to have a diet that focuses on fruits, vegetables, complex carbohydrates, lean protein, and healthy fats while cutting out processed higher-caloric foods. If you look at this particular list, it almost perfectly matches the diet that Sardinians typically focus on.
“[It shows] a correlation of low saturated fat and high fruit and vegetable intake (a.k.a more antioxidants and phytonutrients) as a factor in the picture of longevity for centenarians,” says Michalczyk. “Again pointing to the fact that there is something to a large focus on plant foods versus meat sources of protein.”
One of the points made in this Down to Earth episode was how the Sardinians eat lots of whole, natural foods, and never eat too much of it. They keep their portions smaller.
“One of the factors contributing to ‘overall healthiest countries’ [in a recent report] was percent obesity,” says Rachel Paul, PhD, RD from CollegeNutritionist.com. “Avoiding overeating and excessive weight gain is important for overall health. Reducing total calorie intake in fact has been linked to an extended lifespan, a lower likelihood of disease, and a reduction of belly fat. As excess total calories leads to weight gain, reducing total calories is important for those looking to lose weight. Specific foods do matter, but so also does total calorie intake.”
A diet focused on natural, whole foods can help with longevity.
Pane Carasau, a Sardinian flatbread, is a staple for this small Italian island and dates back even before 1,000 B.C. It was one of the foods Efron made on the show, as well as a small bowl of homemade pasta. Both dishes are common for Sardinian households, along with their minestrone soup, which is made completely of whole, natural ingredients (such as vegetables and potatoes).
The Sardinian diet closely reflects the Mediterranean diet. U.S. News & Worlds Report ranked it the Best Overall Diet in 2020 and is still considered one of the most popular. It is named after the countries bordering the Mediterranean Sea (such as Sardinia, Italy) and it focuses on produce, nuts, olive oil, fish, whole grains, and yes, wine. Paul says many reports around the healthiest countries in the world have similar commonalities in terms of diet, focusing on vegetables, fish, and legumes. And of course, fewer sweets and highly-processed foods.
Yes, the Sardinians follow a high-carb diet, but their carbohydrate intake looks vastly different compared to what we may think.
“Focusing on whole, real foods, compared to processed foods, is also often helpful in managing total calorie intake,” says Paul. “In this sense, if a person is adding into their diet vegetables, legumes, and whole grains, versus regular (not diet) sodas and sugary candies, the switch of type of carbohydrate is likely beneficial.”
“Complex carbohydrates are full of fiber, B vitamins, and other nutrients,” says Goodson. “The fiber helps with satiety and thus can help people manage hunger and fullness better. Lots of research supports high-fiber, complex carbohydrates as a component of healthy weight management. Plus, the fiber in complex carbohydrates can help with lowering cholesterol and improving gastrointestinal health, which long term can lower risk for other diseases.”
“The thing I think that is super important to remember is the type of carbs they are eating vs the types of carbs that are typically high in a western diet,” says Michalczyk. “Sure they may be enjoying a traditional Italian pastry every once in a while, but that is very different than a pre-packaged bakery muffin packed with fats and oils to preserve its shelf-life. ”
Numerous factors can result in longer life, not just diet.
While diet is obviously a huge portion of longevity, for the Sardinian people, there are many factors at play. Genetics is a big one. One genealogist found that 77% of the centurions he studied had a lineage that traced back to the same five names after 500 years.
Physical activity is also a factor. It is a very large part of Sardinian culture. No, it’s not all running and bodybuilders. It’s people taking daily walks or having jobs that require a good amount of movement. Shepherding is one of the oldest professions of the area, and the average shepherd walks 5 to 13 miles a day.
Lastly, the low-level stress and mental state of those who live in Sardinia is very different compared to a fast-paced, “hustle” culture that is highly encouraged in a place like the United States. Efron and Olien commented on the low-stress lifestyle, and also how community plays such a huge role in overall health for the Sardinians.
“Yes, I think diet is a huge part of it but you can’t look at just protein or carbs on their own,” says Michalczyk. “It’s the healthy habits, the low-stress lifestyle, the genes, the environment, and the diet (underscoring how the food is grown and how the food is prepared). And I would even say how it’s consumed—not in front of the TV or computer screen solo, but rather with others, slowly. Of these centenarians that all contribute to their longevity.”
So does this mean eating more pasta and less steak will conclude a longer life? Not exactly. It’s a combination of things. Focusing on real, whole foods (including complex carbs), limiting animal protein intake (which is different from protein that comes from plants), moving your body, and prioritizing a stress-free life can all factor in. And of course, a glass of red wine won’t hurt.