** Note that my personal opinion about grapefruit has changed since this post was originally written. I now believe that some grapefruit are delicious and they do not all taste like liquid garbage.
The Instigator
The morning of February 9th, I ate a grapefruit. Not because I particularly wanted or enjoy grapefruit, but because we had one, and I assumed it was an orange.
I made this assumption based on the following logic and known information:
- My partner bought the fruit
- My partner does not like grapefruit
- Most importantly, grapefruit look essentially the same as oranges, (Note: sphereical, orangish color) especially to people who are unfamiliar with them, e.g., myself.
Regardless of how this situation came to be, the fact is that I ate the grapefruit and it made me think of a couple of things.
First, it is a ‘trash fruit’, a category of fruit I have derived, reserved for fruit that are simultaneously delicious and disgusting. Much like the durian, known for its charming blend of creamy vanilla and rotting garbage, grapefruit has a delicious background notes masked by the bitter flavor, with a simultaneous numbing effect. Despite the inherent flaws of the grapefruit (e.g. partially disgusting, falsifying itself as an orange), it’s a fruit I would eat without complaint.
Secondly, eating this grapefruit sparked the memory of ‘The Grapefruit Diet’, a fad I heard much about while I was growing up, and an important question – why? Why grapefruit and not a more delicious fruit? Is there something about grapefruit that makes it better for you than say, its delectable cousin the orange?
The Hypotheses
In pondering this question, I have come up some hypotheses before I do some online research into the possible whys:
- After you eat a grapefruit, the acidity makes everything that comes after it taste like dirty socks and wet cardboard, assisting oneself from preventing additional consumption
- There is a believed benefit to grapefruit that people think other fruit lack
- People possibly believe this because there’s a weird phenomenon where people think things that taste terrible are good for you
The Research
Origin of the Grapefruit
Grapefruits originate from Barbados – an island in the Caribbean close to South America – and is a hybrid of two citrus species, the (sweet) orange and pomelo. Interestingly, the orange itself is a hybrid between the pomelo and the mandarin; therefore the grapefruit is something like mandarin x pomelo x pomelo.
- Grapefruits are high in fiber and vitamin C.
- Interesting and important fact: there is substantial evidence that grapefruit can interfere with certain medications, particularly for blood pressure or arrhythmia.
- This occurs because the grapefruit (and some related fruits, including the pomelo) contain furanocoumarins, a class of chemicals that disrupt the absorption of certain medications. In most cases, the furanocoumarins allow the medications to enter the bloodstream more quickly, increasing the likelihood of side-effects such as liver damage.
- There are other foods that interact with other medications, please be sure to read about these possible interactions in the inserts that come with your medication. You can read more about these interactions at STAT news and USA Today.
Background of the Grapefruit Diet
According to multiple sources, the grapefruit diet has existed since at least the 1930s in the US, and either is, or was, commonly known as the Hollywood Diet. It appears to be one of the longest lasted diet fads.
Logistics of the Grapefruit Diet
Length of Time
Classically, a short term diet ranging from 10 to 12 days.
Sustenance and Caloric Intake
Generally, a low caloric diet, restricting caloric intake to under 1,000 calories a day, generally considered too few calories for most people. Many versions of this diet seem to emphasize consumption of protein.
According to Web MD, the classic version of this diet also includes:
- Cutting back on sugars and carbs
- Avoiding certain foods, such as celery and white onion (what, why?)
- Eating more foods high in protein, fat, and/or cholesterol (e.g. eggs, red meat)
- Having grapefruit or grapefruit juice with/before every meal
One source calls it a very low-calorie diet (VLCD), which is not a good weight loss solution for many people.
- I did some minimal research into VLCDs, and found that some people/organizations, including the UCLA Center for Human Nutrition, seem to believe they are acceptable and healthy when used appropriately. At UCLA, the primary use of VLCDs is for ‘severely or morbidly obese individuals who must lose or with to lose large amounts of weigh as rapidly as possible in a safe manner.’
- Despite looking into them and seeing they seem… accepted, I think that other options are generally better (BUT I’M NO EXPERT)
There are also more recent versions of this diet, which appear to be less focused on starving yourself (good), but tout the fat-burning idea (… probably not true).
How it Works (Supposedly)
The reason the diet is so popular stems from people claiming that an ‘enzyme’ in grapefruit helps our bodies burn fat. According to sources, there is no evidence of this enzyme.
Outcomes and Effectiveness
Overall, you can lose weight on this diet. However, you can lose weight on any diet – if no one lost weight using it, it probably wouldn’t be so popular. Most diets that consist of short term changes, where an individual reverts back to their previous dietary and exercise habits, are known to gain any lost weight back.
Web MD cites Kathleen Zelman (MPH, RD) who says “grapefruit doesn’t burn fat”, and suggests the diet works by making participants feel more full, possibly from the water content of the fruit.
Studies that test the impact of grapefruit
*I have not verified or validated these studies.
Free dieting [7] cites a study by the Scripps Clinic that claims that the grapefruit assists in fat loss. Over a 12 week pilot study, 100 men and women participated by either eating half a grapefruit with each meal, or drinking a serving of grapefruit juice three times a day. These participants, on average, lost more than 3 pounds. However, this website fails to describe other components of the study, such as other dietary or exercise requirements.
App for health [3] provides details on two studies, the first simply stating that “a new study (no citation) reported women who ate grapefruit [were] thinner and has smaller waistlines than those who didn’t eat the fruit.” Without knowing more about the study, my immediate thoughts are that this is a study that is looking solely at second hand data, which might just mean that people who eat more grapefruit are aware of the grapefruit diet and are more concerned about their weight. Additionally if this is a study with an experiment and control group, there should be a third group that eats other fruit with similar nutritional properties (orange? pomelo?) in place of grapefruit to test if the impact is just from… adding a fibrous and nutritious fruit to one’s diet.
A second study is cited by App for health [3] was conducted by Vanderbilt University. Researchers placed obese participants on a 12-week diet that included grapefruit or grapefruit juice at every meal (similar to the Scripps Clinic study). In this study, participants lost an average of 15 pounds (the difference in weight loss between this and the Scripps study is likely that Scripps Clinic participants were not obese).
The Conclusion
The grapefruit diets kind of works, but not really, but maybe. My recommendation, as a person who of all the diets that exist, has only done minimal research on this one, is that… you can add grapefruit to your diet if you want, especially if you like grapefruit. I would only integrate the limited calorie or other recommendations based on your own needs, and ideally a conversation with a dietician.
Looking back at my hypotheses:
- After you eat a grapefruit, the acidity makes everything that comes after it taste like dirty socks and wet cardboard, assisting oneself from preventing additional consumption
- There is a believed benefit to grapefruit that people think other fruit lack
- People possibly believe this because there’s a weird phenomenon where people think things that taste terrible are good for you
1 is kind of true, except that it appears to be based on water content and fullness, opposed to disgustingness and lack of appetite.
2 is definitely true, whether they are correct is a different mystery.
Hooray! Research! Kind of! Secondary sources!