A large study following over 400,000 Europeans for more than 10 years found that eating more healthy plant foods may reduce the risk of developing multiple serious diseases like cancer, heart disease, and diabetes at the same time. The protective effect was strongest in people under 60 years old. However, not all plant foods are equal - unhealthy plant foods like refined grains and sugary drinks may actually increase disease risk. This suggests that the quality of plant foods matters more than simply avoiding animal products.

The Quick Take

  • What they studied: Whether eating healthy plant foods protects against developing multiple serious diseases (cancer, heart disease, and diabetes) at the same time, and if this protection varies by age
  • Who participated: Over 407,000 healthy adults aged 35-70 from six European countries, followed for about 11 years
  • Key finding: People who ate more healthy plant foods had an 11-19% lower risk of developing multiple diseases, with stronger protection in adults under 60
  • What it means for you: Focus on healthy plant foods like vegetables, fruits, whole grains, and nuts rather than just avoiding meat - but start these habits earlier in life for maximum benefit

The Research Details

Researchers followed two large groups of healthy European adults for over a decade, tracking their eating habits and health outcomes. Participants filled out detailed food questionnaires about what they typically ate. The researchers then watched to see who developed cancer, heart disease, or diabetes, and specifically looked at people who developed two or more of these conditions. They created scores to measure how much people ate healthy plant foods (like vegetables, fruits, whole grains) versus unhealthy plant foods (like refined grains, sugary drinks, processed foods).

This type of long-term observational study is valuable because it follows real people living their normal lives over many years. Unlike short-term experiments, it can capture the long-term effects of dietary patterns on serious diseases that take years to develop.

The study’s large size and long follow-up period make the results more reliable. However, since researchers observed rather than controlled what people ate, they cannot prove that plant foods directly caused the health benefits - other healthy behaviors might also play a role.

What the Results Show

People who scored higher on healthy plant food eating had significantly lower rates of developing multiple diseases. For every 10-point increase in healthy plant food score, the risk dropped by 11% in one study group and 19% in another. This means that people who ate the most healthy plant foods were much less likely to end up with combinations like cancer plus diabetes, or heart disease plus cancer. The protection was strongest in people under 60 years old, suggesting that starting healthy eating habits earlier in life provides greater benefits.

Unhealthy plant foods told a different story. People who ate more refined grains, sugary drinks, and processed plant foods had a 22% higher risk of developing multiple diseases in one of the study groups. This shows that simply eating plant-based isn’t enough - the quality and processing level of plant foods matters significantly.

Previous research has shown that plant-based diets can reduce individual disease risks, but this is one of the first large studies to look specifically at preventing multiple diseases simultaneously. The age-related findings are relatively new and suggest that dietary interventions may be most effective when started in middle age rather than later in life.

The study only included Europeans, so results may not apply to other populations. Researchers relied on people reporting their own food intake, which can be inaccurate. The study couldn’t account for all possible factors that might influence both diet choices and health outcomes, such as access to healthcare or genetic differences.

The Bottom Line

Focus on eating more vegetables, fruits, whole grains, nuts, and legumes while limiting refined grains, sugary drinks, and highly processed plant foods. The evidence suggests moderate confidence that this approach may reduce your risk of developing multiple serious diseases, especially if you start these habits before age 60.

Middle-aged adults (35-60) may benefit most from adopting these dietary patterns. People with family histories of cancer, heart disease, or diabetes should pay particular attention. However, older adults shouldn’t ignore these findings - they still showed some benefit, just less dramatic.

The study followed people for over 10 years before seeing clear benefits, suggesting that consistent long-term dietary changes are needed rather than short-term fixes. Benefits may become apparent after several years of sustained healthy eating.

Want to Apply This Research?

  • Track daily servings of healthy plant foods (vegetables, fruits, whole grains, nuts, legumes) and aim to gradually increase your total to 8-10 servings per day
  • Replace one refined grain or processed food item daily with a whole plant food - such as choosing brown rice over white rice, or an apple instead of fruit juice
  • Create a weekly plant food diversity goal, tracking how many different types of vegetables, fruits, whole grains, and legumes you eat each week to ensure variety and nutritional completeness

This research shows associations between diet and disease risk but cannot prove causation. Individual results may vary based on genetics, lifestyle, and other factors. Consult with healthcare providers before making significant dietary changes, especially if you have existing health conditions or take medications.