Does eating a lot of cacao help you live longer?
In large studies, people who eat chocolate regularly have a lower risk of cardiovascular disease and early death, but it has not yet been proven that chocolate itself is the cause. Small amounts of dark chocolate fit perfectly well into a varied diet.
In a large study of more than 27,000 people, men who ate more chocolate had a 9 to 12% lower risk of dying than men who ate the least. This does not prove that chocolate itself is the cause: people who eat a lot of chocolate may also live more healthily in other ways.
The strongest evidence relates to the heart. Many studies combined, following more than 900,000 participants, show that every extra 5 grams of chocolate per day is linked to a 2% lower chance of cardiovascular disease. In addition, smaller but carefully controlled studies show that the flavanols in cacao measurably lower blood pressure: by an average of almost 6 mmHg systolic and more than 3 mmHg diastolic. This is a biologically well-explained effect, not merely a statistical association.
Blood vessels also become more flexible. Both after a single use and with longer-term use, the ability of blood vessels to widen improves. A small controlled study in healthy people aged 55 and older found that after 30 days of taking 500 mg of cacao flavanols per day, early signs of heart stiffening were also reduced. That sounds promising, but the study included only 63 participants, so further confirmation is needed.
One large study also found 12% less cancer-related death among people with higher chocolate consumption. This is based on a single study and tells us too little to draw firm conclusions. Furthermore, no controlled study has shown that chocolate directly extends lifespan. Review articles also mention beneficial effects on insulin, fat metabolism and gut bacteria, but at the same time acknowledge that the right amount, type and timing have not yet been properly established. Chocolate is also energy-dense: in large quantities, the calories and sugars may offset the benefits. Dark chocolate with a high cacao content delivers the most flavanols with the least sugar.
This answer draws on several large studies in which people were followed for many years, a summary of 21 such studies involving more than 900,000 participants, and a number of smaller controlled studies on blood pressure and heart function. The link with lower death rates is consistent, but no study can prove cause and effect: people who eat more chocolate may also live more healthily in other ways. The researchers themselves emphasise that solid evidence for a direct extension of lifespan is still lacking and that the optimal amount and type of chocolate have not yet been established.