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Grapefruit is a relative newcomer to the fruit bowl. Our hunter-gather forebears would not have bumped into it in the forest. But they may have met its parents, the pummelo and the orange because it’s a shining example of citrus doing what comes naturally – cross pollinating. The deed was probably done in Barbados sometime in the eighteenth century (the parents were immigrants from Asia). Now fast forward a hundred years to 1823 to Odet Philippe planting the first grapefruit seeds in Florida and the beginnings of a billion-dollar American success story that was massively boosted from the 1930s by fad diets extolling its miraculous “fat-burning” powers.

Does it have them? No it won’t burn off the fat or melt the pounds report researchers who looked at the evidence for the effectiveness of consuming grapefruits (Citrus paradisi) on body weight, blood pressure, and lipid profile in a systematic review. Their meta-analysis failed to reveal a significant difference between grapefruits and controls re body weight, but did show a decrease in systolic blood pressure. However, they point out that the paucity of randomised controlled trials, the short durations of the interventions, and the lack of an established minimum effective dose limit the conclusions that can be drawn about the effects of grapefruit on body weight and metabolic parameters. So we end up with the usual “more studies needed”.

What’s in grapefruit?

While it may not burn fat, a small grapefruit (about 210g or 7½oz) will add zest to your day and deliver more than 100% of your daily dose of vitamin C and provide 240 kilojoules (57 calories), 2g protein, no fat, 10g carbs (sugars), 1g fibre, 250 mg potassium. It has a very low GI (25). In fact, fresh grapefruit has the lowest GI value of all fruit tested so far. It’s not just the acid that has a blood glucose-lowering effect, it’s also the pectin (a type of soluble fibre). Canned grapefruit segments (GI 47) and commercial grapefruit juice (GI 48) are easy year-round options when fresh fruit isn’t available.


Med Alert: Some compounds in grapefruit can interact with some medicines making the dose stronger or weaker than it should be. So, check with your doctor or pharmacist about potential problems with any prescription medicines you take.