Breakfasting on half a grapefruit has long been seen as one of the healthiest ways to start the day, but the idea it could help you lose weight was dismissed as a fad decades ago. The old miracle grapefruit diet popular in the 1980s has been superseded by more ‘scientific’ weight loss diets, including low-carb diets, high GI diets and green juice diets.
The old miracle grapefruit diet popular in the 1980s has been superseded by more ‘scientific’ weight loss diets, including low-carb diets, high GI diets and green juice diets.
But now it looks like the people who swore by grapefruit as a weight loss aid were right all along.
A 2014 US study, published in the peer-reviewed journal PLOS ONE by the University of California in Berkley, reported that grapefruit, which contains about 36 calories per serving, helped mice to stay slim. Researchers found that mice fed a high-fat diet gained 18 percent less weight when they drank clarified, no-pulp grapefruit juice compared with a control group of mice that drank water. A potent chemical in grapefruit is believed to offer the benefit, although it isn’t yet proven. Experts believe that the positive weight-loss effects of grapefruit juice happen because it lowers insulin levels. Insulin is a hormone that regulates the absorption of glucose, or sugar, in the body; excess insulin in the body can cause weight gain.
According to a 2013 study of 100 obese men and women by the Scripps Clinic in San Diego, California, people who ate grapefruit three times each day before a meal got the most benefit, losing an average of 3.6 pounds over a 12 week period. Some participants lost more than 10 pounds – and that was without making any other changes to their normal diets. Those who drank a glass of grapefruit juice before each meal lost an average of 3.3 pounds but those who ate a grapefruit-free diet recorded no weight loss at all. ‘The whole fruit is definitely the best option,’ says Abigail, a clinical dietitian and the founder of edietitians.com. ‘Whether or not we can prove that grapefruit helps weight loss, we know that whole grapefruit contains lots of fibre, which aids digestion and bowel health. It’s also the fibre which is probably responsible for grapefruit’s ability to reduce levels of bad LDL cholesterol in the blood. ‘It binds to the LDL cholesterol and allows it to be passed out harmlessly through the body,’ explains Abigail. Some scientific evidence supports grapefruit’s cholesterol-reducing properties. In a clinical study published in the 2006 issue of “Journal of Agricultural and Food Chemistry,” researchers found that, although red grapefruit had higher antioxidant potential than white, both white and red grapefruit decreased serum lipid levels in coronary atherosclerosis patients.
Grapefruit is low in sugar, unlike grapefruit juice which is essentially the concentrated sugars of many grapefruits in a single glass. Grapefruit is a source of vitamin A, one half contains 6.4 percent of the daily recommended allowance. Vitamin A is necessary for healthy vision and for the maintenance of teeth and skeletal and soft tissue. Grapefruits have many other incredible properties which are still under investigation. The fruits contain phytonutrients called liminoids, which seem to help control the activity of genes in cancer cells, activating genes that promote cancer cell death, according to a study published in the “Journal of Biological Chemistry” in 2011. As a result, consuming limonoid-rich grapefruit might help shield you from cancer. People suffering from osteoporosis may also get some benefit from eating
grapefruit as part of their diet. A US study published in 2008 revealed that grapefruit could reduce bone loss in rats. ‘There are some interesting small studies that show there is potentially some bone benefit, but it’s not yet an established fact that grapefruit can help,’ cautions Sarah Leyland, chief nurse adviser to the National Osteoporosis Society. ‘But it’s certainly not going to do you any harm if you enjoy grapefruit for breakfast or a glass or two of grapefruit juice with a meal, and it might do your bones some good.’
And the fact that grapefruit seems to reduce levels of insulin in the blood may be good news for diabetics in future. Diabetes UK, commented: ‘If grapefruit does significantly lower insulin levels this could be a potentially exciting discovery. We will be following any further research in this area closely to establish if grapefruit could provide genuine benefits.
While grapefruit seems to be worth including in a balanced diet, dietitian Abigail warns against adopting anything like the old ‘Grapefruit diet’ which advocated 800 calories a day with a heavy emphasis on grapefruits, and as much black coffee as you could drink. ‘Grapefruit as part of a varied balanced diet may help with weight loss. Further research is needed to understand the use of grapefruit in the role of weigh loss. Eating a diet mainly based on grapefruit is unbalanced, nutritionally incomplete and potentially dangerous.’
And for some people, eating grapefruit can be detrimental to their health. The fruit packs a powerful acid punch and is one of the top 10 foods to cause acid reflux and heartburn, alongside coffee.
Christine, 37, a coffee barista from Woking, who runs her own mobile gourmet coffee company Groundcafe, can drink her own specialist coffees without ill effects, but eating a single slice of grapefruit leaves her in agony. ‘I’ve always loved grapefruit. I grew up with grapefruit in the fruit bowl all the time because my father had a fruit stall. I love the smell and the bright yellow colour, but I don’t touch it because it gives me such terrible acid indigestion.’
Dr Louise Selby, a GP based in Guildford and founder of the Guildford Private General Practice, agrees that grapefruit can cause problems in some people. ‘Like other citrus fruits, grapefruit contains acids which can cause excess gastric acid, particularly if eaten on an empty stomach.’ She recommends Over The Counter remedies like Gaviscon to alleviate symptoms and neutralise the acid.
Worryingly, grapefruit can also interfere with the absorption of a range of drugs and medications, leading to potentially dangerous consequences. This is because it contains a group of chemicals, furanocoumarins, which can affect drug metabolism – the amount of time it takes for a drug to be broken down by the body.
‘If patients are using statins, they should minimise their intake of grapefruit because the fruit can affect the way that the body metabolises the drug and increases absorption through the gut wall. This raises levels of statins in the blood stream which may lead to a range of side effects, including muscle breakdown and even kidney failure.’ Grapefruit also increases the body’s absorption of warfarin, used to thin the blood. Unsuspecting patients who eat grapefruit may find they suffer from skin bruising and even internal bleeding. ‘Grapefruit juice has the same effect as grapefruit and both should probably be avoided by patients on these medications,’ says Dr Selby.
Alexa, who is now slim and toned and has recently taken up boxing, credits grapefruit for her transformation and says she won’t be changing her grapefruit routine any time soon. ‘I’ll stick with grapefruit now, although the after taste is a bit bitter. But I know that the goodness is in the bitterness and that’s all that matters to me.’