Can grapefruit juice prevent weight gain?
By Paris Owen, Nutrition Student.
The Grapefruit Juice Diet, otherwise known as the ‘Hollywood Diet’ has existed for over 80 years. It claims that an enzyme within grapefruit juice can ‘shed fat’ resulting in the loss of a whopping ‘10 pounds (4.5kg) in 10 days’. Although previously disregarded as a fad diet, new research warrants grapefruit juice may play a greater role in weight loss than we once thought.
Leading researchers Andreas Stahl and Joseph Napoli from the University of California in Berkeley recently studied the affects of grapefruit juice on mice fed high fat diets. They wanted to test the magical ‘slimming’ properties of grapefruit, which were previously backed a small number of conflicting human studies. The researchers state they were ‘skeptical’ going into the study, however the results were so surprising that many of their recordings had to be re-checked!
o Mice were divided into groups, which were fed either pulp-free grapefruit juice or water.
o They were placed on a high fat diet (60% from fat) for 100 days.
o Results found that mice fed a high-fat diet gained 18% less weight when they drank pulp-free grapefruit juice compared with mice that drank water.
o Juice-drinking mice also showed better levels of blood sugars, insulin (a hormone responsible for the storage of fat) and triglycerides (fats associated with ‘plaque’ build-up in arteries).
o Researchers determined the compound naringin was responsible for improved blood sugar, insulin and triglycerides, however the compound responsible for weight loss is unknown.
This study provides evidence that grapefruit juice plays a role in weight gain prevention when mice consume a high fat or ‘westernised’ type of diet. It should be noted that this study does not reflect results found in previous human studies, which have shown to be conflicting. It should also be noted that the California Grapefruit Growers Cooperative funded the study. Although researchers state the funders had no control over the study, results should be treated with caution.
Although this study shows grapefruit can prevent some weight gain in mice, it does not reflect what would typically happen in humans. Most studies in humans at the moment are conflicting and more research needs to be done. So there’s no need to start guzzling litres of grapefruit juice just yet! Grapefruit can however be incorporated into your diet to add more variety, colour, flavour and nutrients!
HOW TO EAT MORE GRAPEFRUIT THIS SUMMER
- Make a fresh fruit salad including grapefruit, strawberries, blueberries, grapes, pineapple and orange.
- Feeling something a little sweeter? Try a refreshing grapefruit sorbet.
- Make some grapefruit ice cubes by chopping up and popping in the freezer.
- Toss pieces of grapefruit in with your salad at lunch or dinner. Don’t be afraid to add other pieces of fruit like pear, mango and watermelon to compliment your summer salad!
- Quench your thirst with a nutrient-packed grapefruit juice.
GRAPEFRUIT HAS BOTH ADVANTAGES & DISADVANTAGES
o High in vitamin C, which is a powerful antioxidant shown to reduce severity of cold symptoms.
o High in vitamin A, which helps to maintain healthy skin and promotes good vision.
o High in lycopene, an antioxidant shown to reduce the risk of developing prostate cancer (red and pink varieties only).
o High in a soluble fibre, called pectin that can help to lower LDL cholesterol, or ‘bad’ cholesterol.
o Very low in calories, providing about 40 calories for a half a medium size piece compared to an average of 70 calories for other types of fruit.
o Grapefruit juice can make certain pharmaceutical medications stronger by inhibiting the enzyme, which is used to break them down. It is therefore important that you consult with your GP if taking medication prior to introducing grapefruit juice into your diet.
o Grapefruit can be a bit bitter depending on the colour. If you have a sweeter tooth, choose pink or red varieties.
Hi fellow food lovers! My name is Paris Owen and I am currently undertaking a Masters in Nutrition and Dietetics at University of Wollongong. I am also a university-qualified Nutritionist, graduating last year with a Bachelor of Science in Nutrition. I work with Body Bloom, a women’s fitness training group, providing specialised sports nutrition advice and meal plans. Bondi Farmers Markets is where you will find me on Saturdays making nutritious goodies with an incredible team at the Inside Out Nutritious Goods stall.
I like to take an evidence-based approach for nutritional recommendations to ensure the best health outcomes for each unique individual. I also like to approach health in a holistic way incorporating physical, mental and spiritual wellbeing. In the future, I will become an Accredited Practicing Dietitian, working in the public health system and eventually, in private practice. I am particularly interested in food allergies and intolerances and sports nutrition, however there are so many other areas I am yet to discover!
Chudnovskiy, R, Thompson, A, Tharp, K, Hellerstein, M, Napoli, Stahl, A 2014, ‘Consumption of Clarified Grapefruit Juice Ameliorates High-Fat Diet Induced Insulin Resistance and Weight Gain in Mice’, PLoS ONE, vol. 9, no. 10, pp. 1-11.
Sarah Yang 2014, Grapefruit juice stems weight gain in mice fed a high-fat diet, UC Berkeley News Center, viewed 1 November 2014, <http://newscenter.berkeley.edu/2014/10/08/grapefruit-juice-stems-weight-gain/>.
Megan Ware & Helen Yuan 2014, What are the health benefits of grapefruit?, Medical News Today, viewed 5 November 2014, <http://www.medicalnewstoday.com/articles/280882.php>.