No surprise here: people who follow healthy diets tend to lead longer, healthier lives. But most of the studies backing this assertion compared people who ate well to people who didn't. Does changing your own diet over many years make much of a difference?
In a new study published in the New England Journal of Medicine, researchers found that it did. People who added in some wholesome foods over time—even if they didn't necessarily commit to making over their entire way of eating—improved their chances of living longer.
Researchers looked at data from the same group of people over 12 years to see if those who changed their diet for better or for worse—either by eating more healthy foods or more unhealthy foods—lived longer or died earlier than those who didn't change what they ate.
The study involved more than 73,700 men and women enrolled in two long-term health studies. People were asked to record their typical diet at the start of the study, then to fill out food questionnaires every four years for 12 years after that. The researchers then scored the diets by ranking the healthfulness of food components including vegetables, fruit, whole grains, nuts, red meat, fish and dairy, as well as things like sugar-sweetened beverages. Using the reports, researchers were able to gauge how much of a person's eating habits changed over time.
People who said they ate more healthy foods over time had a lower risk of dying during the study period. The more healthy foods people added to their diet, the lower their risk. It worked the other way, too. Those who ate more unhealthy foods over time saw their risk of dying during the study go up.
The good news is that adding in any amount of healthy foods may help lower the risk of early death. Improving diet by just 20% was linked to a 8-17% lower risk of premature death. (Eating 20% more of unhealthy foods, in contrast, contributed to a 6-12% increased risk in death.)
Even cleaning up one meal a day seems to help. Swapping out one serving of red or processed meat a day with healthier nuts or legumes was linked to any where from an 8% to 17% drop in the risk of premature death.