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Can Grapefruit Help You Lose Weight?

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Reducing dietary energy density is an effective way to burn fat and lose weight. Whilst this process is an easy one on paper it can be difficult to know which foods you need to eat, and which ones you need to avoid.

In this article we are going to take a look at the grapefruit – a much researched tropical fruit famed for its sweet and tangy flavor and packed full of nutrients. But can it boost weight loss? 

Here’s what we’ll cover:

  • An overview – what is the grapefruit?
  • The health benefits
  • What do the studies say – does it burn fat?

An Overview of the Grapefruit

The grapefruit is the fruit of the evergreen subtropical citrus tree. It is the result of a hybrid cross between two fruits – the sweet orange and the pomelo, both of Asian origin.

Its Latin name – citrus paradisi – makes reference to its strong sweet, sour taste. It has both a tart and tangy juiciness and a vibrant red-orange flesh.

One serving of paradisi contains just over 50 calories and 2 grams of fiber, but holds a number of nutrients that can boost health. These include vitamin C which can support your immune system, as well as fiber which can increase fullness and delay gastric emptying. You’ll also find vitamin A and D as well as potassium and calcium here too.


The Health Benefits of The Grapefruit

One of the main nutrients found in the fruit is Naringenin. It has antioxidant and anti-inflammatory properties and has been found to boost fat loss and decrease blood lipids in rat studies [1]. Research has shown that this flavonoid can also treat degenerative diseases, cardiovascular disorders and also reduce cholesterol.

The flesh contains lycopene which is found in reddish fruits and vegetables – this phytochemical, carotenoid nutrient has been found to reduce the risk of prostate cancer [2].

Additionally, it also contains pectin – a type of fiber found in ripe fruits. Studies have found that this fiber can decrease cholesterol by over 7% over a 16-week period [3].

The seed extract of the fruit has been found to have anti-microbial properties, being able to fight candida, fungal infections and urinary tract infections.

Back in the 1930s a short-term weight loss plan called the ‘grapefruit diet’ was introduced and subsequently became popular in the 1980s [4]. It claimed that due to enzymes in the fruit, fat loss could be accelerated if half a grapefruit was eaten with every meal – as long as it was done in conjunction with a calorie deficit.

Whilst this diet quickly became a bit of a fad due to its restriction on daily number of calories, did it really help people burn fat? Let’s have a look at what the scientific research says…


Key Point: The grapefruit contains nutrients such as vitamin C, lycopene and naringenin that have all been show to improve health.

Does Grapefruit Boost Weight Loss?

There are a small number of research papers available analyzing the effects of this fruit on weight loss and fullness, as a ‘preload’ – a food eaten before a main meal. Here’s what the main studies say:

#Study 1: [5]

In this study, published in Nutrition and Metabolism, 85 obese adults were split into one of three groups.

  • Group 1: 1/2 grapefruit
  • Group 2: Grapefruit juice
  • Group 3: Water.

Each of the participants were put on a calorie-restricted diet for 12 weeks and asked to eat or drink their preload prior to breakfast, lunch and dinner.

When the preload was combined with a restricted diet, all three groups lost weight – on average 7.1%. They also all lost fat around the belly, legs and body.

Additionally, all volunteers reduced their meal consumption by 20-30% by including a preload. The type of preload was irrelevant though as there were no significant differences between group. 

So on one hand the study showed that this tropical fruit could help reduce fat, weight and food consumption – but no differently to that of a glass of water. 

#Study 2: [6]

This study wanted to test if grapefruit could not only boost weight loss, but also if it could improve insulin resistance too. A group of 91 obese volunteers were randomly assigned into one of the following test groups over a 12 week period:

  • Group 1: Placebo capsule and 7 ounces apple juice
  • Group 2: Placebo capsule and 7 ounces grapefruit juice
  • Group 3: Placebo capsule and 1/2 fresh grapefruit

Group 3 lost significantly more weight than the other two groups – 1.6kg. There was also a significant reduction in blood sugar after each meal meaning that insulin sensitivity improved too.


Key Point: Grapefruit has been shown to help weight loss and increase feelings of fullness.

Summary – Grapefruit and Weight Loss

The grapefruit is the fruit of the evergreen subtropical citrus tree and the result of hybrid cross between two fruits – the sweet orange and the pomelo.

It is a low calorie food, with one serving containing just over 50 calories and 2 grams of fiber. It is a good source of vitamin C, A and D as well as potassium and calcium. This fruit also contains a number of other bioactive ingredients that can boost health such as lycopene, pectin and naringenin.

Research suggests that eating this fruit can increase feelings of fullness that reduces subsequent meal energy consumption, and can help you lose weight. Whilst there is not an overwhelming amount of studies to draw upon to evidence this, as the fruit has no side effects and can boost health regardless, we suggest you include it in your weight loss plan.

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  1. Cho, KW et al. Dietary naringenin increases hepatic peroxisome proliferators–activated receptor α protein expression and decreases plasma triglyceride and adiposity in rats. Eur J Nutr. 2011; 50(2): 81-88 
  2. Gann, PH et al. Lower Prostate Cancer Risk in Men with Elevated Plasma Lycopene Levels: Results of a Prospective Analysis. Cancer Res. 1999; 59: 1225-1230
  3. Cerda, JJ  et al. The effects of grapefruit pectin on patients at risk for coronary heart disease without altering diet or lifestyle. Clin Cardiol. 1988; 11(9): 589-94
  4. Grieger, L. Grapefruit diets. Your Total Health. 2007
  5. Silver, HJ et al. Effects of grapefruit, grapefruit juice and water preloads on energy balance, weight loss, body composition, and cardiometabolic risk in free-living obese adults. Nutrition & Metabolism. 2011; 8: 8
  6. Fujioka, K et al. The Effects of Grapefruit on Weight and Insulin Resistance: Relationship to the Metabolic Syndrome. J Med Food. 2006; 9(1)