A recent randomized controlled trial investigated whether grapefruit consumption resulted in weight loss. In this study, 74 overweight adults were put on a 6-week diet of either a placebo control diet (no grapefruit) or a diet which included one half fresh grapefruit with each meal (3 meals per day). All participants were encouraged to limit the intake of other fruits and vegetables with high polyphenol and carotenoid such as berries, spinach, sweet potatoes, and tomatoes in order to assess the impact of grapefruit consumption. There was no significant difference in terms of calorie intake between the two groups.
So what this means is that when you take a drug at the recommended dose, your body will be exposed to a therapeutic concentration of the drug for a particular period of time. However, when your CYP enzymes are inhibited, the drug that you took is no longer being properly metabolized, and therefore your body is being exposed to a much higher concentration of the drug for longer periods of time, and this can cause severe side effects and can sometimes be fatal.
So although grapefruit can provide numerous health benefits, it can be a very dangerous fruit to consume especially if you take certain medications that are known to interfere with grapefruit consumption. Always consult with your doctor or pharmacist if you’re a grapefruit eater and are prescribed a new medication or if you take daily medication and are looking to introduce grapefruit into your diet.