Gram Research analysis shows that Black South African adults who ate the most healthy foods had a 31 percent lower risk of dying over 13 years compared to those eating the least healthy diets. Researchers used a diet quality scoring system to measure how much whole grains, healthy oils, and other nutritious foods people consumed. The study found that better diet quality was strongly connected to living longer, though most people in the study weren’t eating enough healthy foods.
A new study followed Black South African adults for 13 years to see how their eating habits affected their chances of living longer. Researchers used a scoring system called the Global Diet Quality Score to measure how healthy people’s diets were. They found that people who ate more healthy foods like whole grains and oils had a much lower risk of dying from any cause during the study period. However, the study also showed that most people in South Africa aren’t eating enough of these healthy foods, which is an important public health concern.
Key Statistics
A 13-year cohort study of Black South African adults published in the Journal of Nutrition in 2026 found that people in the top third for healthy food intake had a 31 percent lower risk of all-cause mortality compared to those in the bottom third.
According to research reviewed by Gram, people who scored highest on avoiding unhealthy foods had a 39 percent higher risk of dying, suggesting that in food-insecure settings, avoiding unhealthy foods may lead to insufficient calorie intake.
The 2026 study found that only whole grains and liquid oils reached desirable intake levels among Black South African adults, indicating widespread low diet quality across the population.
Research shows that the Global Diet Quality Score’s healthy food component (GDQS+) was significantly associated with reduced mortality risk, with a hazard ratio of 0.69 for the highest versus lowest tertile.
The Quick Take
- What they studied: Whether eating a higher quality diet (measured by a special scoring system) helps Black South African adults live longer
- Who participated: Black South African adults aged 30 to 70 years who were part of a larger health study called PURE-NWP-SA. Researchers tracked their eating habits and then followed them for 13 years to see who stayed healthy and who passed away.
- Key finding: People who scored in the top third for eating healthy foods had a 31 percent lower risk of dying from any cause compared to those in the bottom third. People who avoided unhealthy foods had a 39 percent higher risk of dying, which was unexpected.
- What it means for you: Eating more whole grains, healthy oils, and other nutritious foods may help you live longer. However, this study was done in South Africa, so results may differ in other places. Talk to your doctor before making big diet changes.
The Research Details
This was a long-term follow-up study that tracked real people’s eating habits and health outcomes over time. Researchers started by collecting detailed information about what Black South African adults ate at the beginning of the study. They used a tool called the Global Diet Quality Score to grade how healthy each person’s diet was. This score looks at both the good foods people eat (like whole grains and healthy oils) and the bad foods they avoid (like sugary drinks and processed meats).
Then the researchers waited 13 years and checked which participants had passed away and what caused their deaths. They used a statistical method called Cox proportional hazards models to figure out whether people with higher diet quality scores were less likely to die. They also separated the results by sex and age group to see if diet quality affected men and women differently.
This research approach is important because it looks at real people living their actual lives, not just what happens in a lab. By following people for 13 years, researchers could see the long-term effects of diet quality on survival. The study also focused on Black South African adults, a population that hasn’t been studied much before with this particular diet quality tool. This helps fill a gap in our understanding of how diet affects health in African populations.
This study has several strengths: it followed people for a long time (13 years), it adjusted for other important factors like exercise and health conditions, and it was published in a respected nutrition journal. However, the study only measured diet once at the beginning, so we don’t know if people’s eating habits changed over the 13 years. The study also couldn’t prove that better diet caused longer life, only that they were connected. Additionally, the researchers note that the diet quality scores may not work as well in places where people have limited food choices or food insecurity.
What the Results Show
The main finding was clear: people who ate the healthiest diets had significantly lower death rates. Specifically, people in the top third for eating healthy foods (high GDQS+ score) had a 31 percent lower risk of dying compared to those in the bottom third. This difference was statistically significant, meaning it’s unlikely to have happened by chance.
However, the study revealed something surprising about avoiding unhealthy foods. People who scored highest on avoiding unhealthy foods (high GDQS- score) actually had a 39 percent higher risk of dying. The researchers think this might be because in a place with limited food choices, avoiding unhealthy foods might mean eating very little, which could be harmful.
The study found no connection between diet quality and death from heart disease specifically, even though better diet usually helps the heart. This was unexpected and suggests that diet quality might affect overall survival through different pathways than just heart health.
One important finding was that most people in the study had low overall diet quality scores. Only two food groups reached healthy levels: whole grains and liquid oils. This shows that most Black South Africans aren’t eating enough variety of healthy foods.
The researchers looked at whether results differed between men and women and between different age groups. The patterns were similar across these groups, suggesting that diet quality matters for everyone. The study also found that the connection between diet quality and survival was consistent even after accounting for other important factors like physical activity, smoking, and existing health conditions.
This is one of the first studies to use the Global Diet Quality Score in an African population. Previous research in other parts of the world has generally shown that better diet quality reduces death risk, so this study’s main finding fits with what we already know. However, the unexpected finding about avoiding unhealthy foods being associated with higher death risk is new and suggests that this scoring system may need adjustment for populations with limited food access.
The study has several important limitations. First, researchers only measured what people ate once at the beginning of the study, so they couldn’t track whether eating habits changed over 13 years. Second, the study couldn’t prove that diet caused the differences in survival, only that they were connected. Third, the study was done in one specific region of South Africa, so results may not apply to other African countries or populations. Fourth, the researchers note that the diet quality scoring system may not work well in places where people have very limited food choices or struggle with food insecurity. Finally, the study didn’t find a connection with heart disease deaths specifically, which was unexpected and not fully explained.
The Bottom Line
Based on this research, eating more whole grains and healthy oils appears to help people live longer. The evidence is moderately strong for this recommendation. However, people should focus on eating more healthy foods rather than just avoiding unhealthy ones, especially in places where food choices are limited. Anyone making major diet changes should talk to their doctor first, particularly if they have existing health conditions.
This research is most relevant to Black South African adults and possibly other African populations. The findings may also apply to people in other parts of the world, but more research is needed. People with limited access to healthy foods should be cautious about using this diet quality score, as it may not reflect their actual situation. Anyone interested in living longer and reducing their death risk from any cause should pay attention to these findings.
The study followed people for 13 years, so the benefits of better diet quality take time to show up. You probably won’t notice major health improvements in a few weeks or even months. However, eating better can help you feel better and have more energy within days or weeks. The real life-extending benefits likely develop over years of consistent healthy eating.
Frequently Asked Questions
Does eating better food actually help you live longer?
Research shows that eating more whole grains and healthy oils is connected to living longer. A 13-year study of Black South African adults found that people eating the healthiest diets had a 31 percent lower death risk. However, diet is just one factor affecting lifespan.
What specific foods should I eat to live longer according to this study?
The study highlighted whole grains and liquid oils as the most important foods. These were the only food groups where people reached healthy intake levels. Include brown rice, oats, whole wheat bread, olive oil, and other plant-based oils in your daily meals.
Can avoiding junk food alone help you live longer?
Surprisingly, the study found that just avoiding unhealthy foods wasn’t enough and was even associated with higher death risk. The key is eating more healthy foods, not just avoiding bad ones. Focus on adding nutritious foods to your diet rather than just cutting things out.
How long does it take to see health benefits from eating better?
The study tracked people for 13 years, so major life-extending benefits take time. You might feel more energetic within days or weeks of eating better, but the biggest health improvements develop over months and years of consistent healthy eating habits.
Does this research apply to people outside of South Africa?
The study was done in South Africa, so results may differ in other places. However, the basic finding that whole grains and healthy oils support longer life matches research from other countries. Talk to your doctor about how these findings apply to your situation.
Want to Apply This Research?
- Track daily servings of whole grains and healthy oils consumed, aiming for at least one serving of each per day. Log the specific foods (brown rice, oats, olive oil, etc.) and portion sizes to build awareness of intake patterns.
- Set a weekly goal to try one new whole grain food and one new healthy oil-based dish. Use the app to plan meals that include these items and get notifications when you’re approaching your daily targets.
- Review your diet quality score monthly by logging your typical meals. Compare your scores across months to see if you’re gradually improving. Set incremental goals to increase your healthy food intake by 10 percent each month.
This article summarizes research findings and should not be considered medical advice. The study was conducted in Black South African adults and results may not apply to all populations. Diet quality is just one factor affecting health and lifespan. Before making significant changes to your diet, especially if you have existing health conditions, consult with your healthcare provider or a registered dietitian. This research shows associations between diet quality and mortality, not definitive proof of cause and effect. Individual results may vary based on genetics, overall lifestyle, and other health factors.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.