How harmful are trans fats, exactly?
Industrial trans fats are demonstrably harmful to your heart and blood vessels, even in small amounts. Avoid them by checking ingredient lists for 'partially hydrogenated oil'.
Industrial trans fats raise LDL cholesterol (the 'bad' cholesterol) and lower HDL cholesterol (the 'good' cholesterol). That combination is particularly unfavourable, and both dietary studies and studies in people confirm this effect.
The heart risk is concrete: for every 2% of your daily calories that comes from industrial trans fats, the risk of a heart attack or death from heart disease rises by 24 to 32%, compared with other fat sources. That is a large effect for a relatively small amount, and many studies following people for years arrived at this estimate.
Beyond cholesterol, trans fats also damage the inner lining of blood vessels, an early sign of hardening of the arteries. They also raise substances in the body that drive inflammation, such as CRP and interleukin-6. Both effects have been found in dietary studies as well as in people followed over time, although the certainty is somewhat lower than for the heart risk.
There are also hints of poorer insulin sensitivity and greater accumulation of belly fat, but those links are still weak and not sufficiently confirmed to make firm statements about. Possible effects on fertility or brain health are mentioned in overview articles but have barely been studied.
Trans fats that occur naturally in dairy and beef or lamb do not appear to carry a measurable increased heart risk at the amounts people normally eat. Gram for gram, they affect cholesterol just as unfavourably as the industrial variety, but intake is usually much smaller. The ban or strict limits that have now been introduced in several countries and by the WHO apply exclusively to industrial trans fats, with the estimate that tens of thousands of heart disease events per year could be prevented if they were removed from the food supply worldwide.
All sources are reviews; no primary studies or combined analyses were supplied as individual references. The strong statements about heart risk are based on studies following large groups of people over time and a combined analysis of multiple studies, as described within those reviews.
How dangerous is belly fat?
Belly fat is a serious risk factor for cardiovascular disease, heart failure, and early death, and the risk grows the longer it stays elevated. A combination of a Mediterranean diet and regular exercise is the best-supported approach to reducing it.
Is the taurine in energy drinks harmful?
Taurine in energy drinks does not appear to be harmful in the short term, but the real risks lie in the caffeine and sugar. If you want a reason to avoid energy drinks, that is the right one.
How bad is eating a lot of salt for me?
Eating a lot of salt is clearly harmful to your blood pressure and your heart, and the risk grows with the amount consumed. Eating more vegetables and fruit helps to temper the effect, but does not replace reducing salt intake.
How healthy is olive oil and what is it good for?
Olive oil, and extra-virgin olive oil in particular, is well supported as protective for the heart and blood vessels, especially when used in place of butter and as part of a varied, plant-based diet.
Is atrial fibrillation dangerous, and what can I do about it?
Atrial fibrillation substantially raises your chances of dying, heart failure, and stroke, and calls for active treatment. Discuss blood thinners for stroke prevention with your doctor, as well as which lifestyle changes make sense in your particular case.
How harmful is prolonged stress really for my heart?
Prolonged stress measurably increases your risk of heart and vascular disease, particularly through work-related stress (10–40% extra risk in large population studies). The effect is real, but smaller than that of smoking or high blood pressure.