New Study: Eating These Fats and Proteins Could Help You Live Longer

A reminder of the benefits of some foods that are considered treats: A new study says a diet balanced in these macronutrients can help combat some of the biggest drivers of death.

It’s why health and nutrition coaches are growing in popularity: Figuring out what to eat to shed weight and feel satisfied can be tough. While in the end, the diet comes down to three basic macronutrients—fat, protein, and carbohydrates—the ratios and types of these nutrients that constitute a healthy diet are often debated.

For example, even though the zeitgeist of past decades suggested fat was pure indulgence, fat is actually a necessary nutrient—some types of fat are even highly protective. The same goes for protein and nutritious carbohydrates: The body needs all these to function and defend against disease.

Now a new study says eating certain fats and proteins could actually help you live longer and ward off cardiovascular disease and cancer—and too much of certain carbohydrates can have the opposite effect.

The study, published January 2, 2024 in the journal Nutrients and conducted by top nutrition and health researchers in China, analyzed over 120 studies, which included information from over 5 million people aged 19 to 99 years old, and analyzed them for the associations between the three macronutrients and longevity, cancer, and heart health.

What the researchers found was that the single biggest factor that led to a longer lifespan was a diet that varied macronutrient sources.

In other words, in terms of relative longevity, it didn’t matter what type of fat people were consuming, but eating a variety of different types of fat did. Unsaturated fats like monounsaturated (MUFAs) and polyunsaturated (PUFAs) were generally associated with fewer instances of heart issues, with the consumption of olive oil, nuts, and fatty fish leading to a potentially longer, healthier life.

Saturated fat, on the other hand, was associated with worse outcomes when it came to cancer, especially when it came from red meat sources.

Even so, total fat intake appeared to prolong life as long as it came from a range of foods.

For protein, increased intake was associated with a lower risk of cardiovascular disease. The researchers theorized that the type of protein—whether it came from a vegetable or animal source—might be the deciding factor. While animal protein was not associated with overall rates of death or cancer, increased animal protein could be implicated in cardiovascular disease. Red meat in particular was associated with the greatest risk to the heart, while fish and poultry saw the greatest protective effect. Choosing plant protein sources like beans, nuts, and grains was also correlated with lower rates of cardiovascular disease.

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Where the study brought a twist was its conclusion on carbohydrates. Carbohydrates, a blanket term that refers to anything starchy or sugary—including fresh fruits, vegetables, and grains to white bread, sweets, and soda—mattered significantly when looking at overall health. “Mounting evidence indicates that high intakes of refined carbohydrates are associated with diabetes, metabolic syndrome, and chronic inflammation, all of which are linked to the progression of cardiovascular disease,” said the authors.

High intake of carbs was associated with an increased risk of death from cardiovascular disease, but consuming the lowest amount of carbs wasn’t without its issues. What the researchers found was that the type mattered, and the ratio was also very important. Considering all of the included studies, an intake of about 50% to 55% carbs was associated with the lowest risk of mortality, they concluded.

They added that continued research on simple and complex carbohydrates was warranted, but replacing fat with carbohydrates could be harmful as a message to people. They said in part, “The World Health Organization’s guidelines suggest reducing total fat intake in exchange for a higher intake of carbohydrates. However, the long-term effects of macronutrients on health outcomes are both incomplete and contradictory.”

Overall, the authors felt strongly that the vast number of studies included in the overall study makes a compelling case that current dietary guidelines are lacking in terms of the message to consume more carbohydrates. They determined that “balanced nutrient intake is essential in the context of an overall healthy eating pattern,” and the quality of nutrients was paramount.

Furthermore, more studies needed to be undertaken to determine how the quality of nutrients affected overall longevity, heart health, and cancer risk. “We found that most studies only reported total amounts, and few studies distinguished the quality of major nutrients. Further understanding the impact of dietary nutrient quality on diseases will help formulate public health policies and dietary guidelines,” they concluded.

What this study means for the average person concerned about healthy eating seems to align with general healthy eating recommendations. In general, try to consume adequate protein, occasionally choosing fish and/or plant-based options, opt for minimally processed carbs that are high in fiber, and stick to unsaturated fats as your main source. As always, keep sugary and processed carbohydrates to a minimum.

Meaghan Cameron, MS
Meaghan has more than 15 years of experience in writing and editing food, travel, fitness, sports, and lifestyle material. Her professional journey began at Reader's Digest, where she honed her skills and developed a passion for creating engaging content. Throughout her career, she has contributed her expertise to renowned platforms such as Food Network, Martha Stewart, Outside Television, and Eat This, Not That! Additionally, Meaghan has valuable experience in radio and video production. Before entering the world of content creation, Meaghan spent more than a decade working in the restaurant industry. This hands-on experience has provided her with insider knowledge and secrets about the workings of the industry. Meaghan holds a bachelor's degree in English from the State University of New York (SUNY) Purchase and a master's degree in publishing from Pace University.