Low-fat or low-carb? Study reveals which diet leads to a longer life

BEIJING, China — Which diet is the “right diet” if you’re looking to live a long and healthy life? There’s no shortage of trendy meal plans out there these days, but for many people, the choice comes down what foods they’re not eating. With that in mind, a new study finds middle-aged adults who avoid foods high in fat are more likely to live longer than those who choose a diet low in carbohydrates.

As people age, they need less energy from food, so study authors say it’s important for older people to get the right nutrients in their diet. Some studies have looked at diets that are low in carbohydrates or low in fats to help with weight loss and heart health. However, recent research suggests that the type of carbohydrates and fats you eat might be more important than just eating fewer of them. For example, eating whole grains instead of refined grains and choosing unsaturated fats instead of saturated fats may be better for your health. However, scientists don’t as know much about how these diets affect the long-term health of older people.

In this study, the researchers looked at six different diets to see how well people followed them. They wanted to find out if these diets were related to how long people lived and what they died from. The study involved over 500,000 older people in the United States. They also wanted to see if replacing low-quality carbs and saturated fats with better options would affect people’s risk of dying.

Researchers from the U.S. and China looked at a large group of people between 50 and 71 years-old from across the U.S. They answered questions about their food habits, health, and lifestyle to help the team understand their diets. People with certain diseases or other health issues were not included, so the final group had 371,159 people.

Study authors used a special survey to figure out what types of foods the participants ate and how often. They looked at the amounts of carbohydrates, fats, and proteins people consumed and created scores to measure how well they followed different diets. These scores helped the researchers understand how healthy or unhealthy the diets were.

To see if these diets affected how long people lived and what they died from, the researchers checked if the participants had passed away and what caused their deaths. They used a statistical method called Cox proportional hazards regression to see if there was a link between the diets and people’s chances of dying.

The researchers also looked at different groups of people, like those with different lifestyles, to see if the results were the same for everyone. They performed additional tests to make sure their findings were reliable, such as checking if the overall quality of the diet was more important than the types of nutrients people ate.

Lastly, the team looked at what would happen if people replaced some unhealthy carbs and fats with healthier options, while keeping the total amount of calories the same. They wanted to see if this change would affect the chances of dying. All of the data was analyzed using a statistical software called Stata, and the researchers considered their findings significant if the results had a very low chance of being a random occurrence.

Choosing your carbs poorly significantly increases risk of death and disease

Results show people who followed a low-carbohydrate diet (LCD) with unhealthy foods had a higher chance of dying prematurely. Meanwhile, those who followed a low-fat diet (LFD) with healthy foods had a lower chance of dying. Participants who smoked or used to smoke had even higher risks of dying if they followed an unhealthy low-carb diet.

When it came to heart-related deaths, the unhealthy LCD also increased the risk, while a healthy LFD lowered the risk. For cancer-related deaths, an unhealthy LCD increased the risk of dying from all cancers and lung cancer, while a healthy LFD reduced those risks.

Swapping out some unhealthy nutrients, like low-quality carbs or saturated fats, with healthier options like plant protein or high-quality carbs, lowered the risk of dying from all causes, heart-related issues, and cancer.

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The study observed people for around 23.5 years and recorded 165,698 deaths. They grouped people into five categories based on their diet scores. For those in the highest category of unhealthy low-carb diets (LCD), the risk of dying increased by 17 percent compared to those in the lowest category. On the other hand, people in the highest category of healthy low-fat diets (LFD) had an 18-percent lower risk of dying than those in the lowest category.

For heart-related deaths, people with the highest unhealthy LCD scores had a 15-percent higher risk compared to those in the lowest category. Meanwhile, those with the highest healthy LFD scores had a 16-percent lower risk of dying from heart-related issues.

When looking at cancer-related deaths, people with the highest unhealthy LCD scores had an 18-percent higher risk of dying from all cancers and a 36-percent higher risk of dying from lung cancer. However, people with the highest healthy LFD scores had lower risks of dying from all cancers and lung cancer.

In short, following a healthy low-fat diet and replacing unhealthy nutrients with healthier options can lower the risk of dying from various causes, including heart-related issues and cancer.

Plant-based alternatives provide even more nutrition

While low-carb diets of any variety had the higher risks of dying from all causes, heart-related issues, and cancer, the other four diets studied showed somewhat lower risks of dying from all causes, but not as much as the healthy low-fat diet.

Previous studies have had mixed results about how carbs affect our health. Some find that too many carbs could be bad, while others report that the right amount of carbs isn’t a problem. This study suggests that it’s more important to focus on the quality of carbs and fats in our diets rather than just the amounts.

The researchers also found that replacing unhealthy carbs and saturated fat with plant protein was better for our health than replacing them with other types of nutrients. This is important because as we age, we tend to lose muscle, and getting enough protein can help prevent this.

In summary, the study suggests that for healthy aging, it’s better to follow a diet low in unhealthy carbs and saturated fat, with a focus on high-quality carbs and plant proteins. It’s never too late to switch to a healthier diet to improve our overall health and lower the risk of dying from various causes.

The researchers do note that the study has some limitations, such as only measuring dietary habits once, potential inaccuracies in self-reported food intake, and the majority of participants being non-Hispanic and highly educated individuals. Also, because it’s a long-term study, the team can’t say for sure that these diets directly cause the changes in health they observed.

The study is published in The Journal Of Internal Medicine.