Research Review: The grapefruit diet - fad or science? Eat half a grapefruit before each meal and lose 1. But can it help with weight loss? A recent study looked at the age- old claim in an effort to get some answers. Introduction — Quack, quack goes the duck“Who’s that waddlin’ down the street. It’s just me ? Yes, I am! Every picture of me’s. Gotta be an aerial view. Now my doctor tells me. There’s just one thing left to do. Grapefruit Diet (Diet!)Throw out the pizza and beer. Grapefruit Diet (Diet!)Oh, get those jelly donuts out of here. Grapefruit Diet (Diet!)Might seem a little severe. Is the grapefruit diet a plan that is healthy or safe? WebMD reviews the pros and cons of this fad diet. Grapefruit Diet (Diet!)I’m gettin’ tired of my big fat rear. Blow, fatty!”– Lyrics from Wierd Al Yankovic’s Hit “The Grapefruit Diet” Lose up to 1. Quack, quack, ding, ding – that statement should set off some warning bells and let you know there is some quackery afoot. Satirized with the usual irreverence and mild cruelty by Weird Al Yankovic, fad diets will never die — not as long as we live in a world where people seek immediate gratification. Unfortunately for many vulnerable or hurried consumers, the appeal of instant results perpetuates the demand for information, products, or plans promising overnight success. The Grapefruit Diet, also known as the Hollywood Diet, or the Mayo Clinic Diet (although it’s not even remotely associated with the real Mayo Clinic), is based on the premise that grapefruit possesses near- magical powers. Proponents of the diet claim that eating half a grapefruit before meals high in protein and fat produces a metabolic reaction that transforms even the meekest office worker into a magnificent fat- burning machine. The thermogenic powers supposedly stem from a special fat- burning enzyme in grapefruit that acts as a catalyst to help your body incinerate high fat foods, which in turn results in fast weight loss. Grapefruit – a thermogenic super fruit? This is all well and good, but did you read the fine print stating that you also need to restrict your total daily calorie intake to 8. ![]() So where do the 8. You guessed it: meat, meat, and more meat. Sounds a bit reminiscent of Atkins, doesn’t it? But actually, Atkins followed the Grapefruit Diet, and not the other way around. Fad diet history lesson. Over eighty years.
![]() The Grapefruit Diet has been around that long. Eighty years ago puts us somewhere in the 1. Pluto was discovered, the Mickey Mouse comic strip first appeared, and Hostess Twinkies were invented (1). ![]() Hmm, I wonder if the Twinkies had anything to do with it? The diet made a big resurgence in the 1. Mayo Clinic Diet.” As you can imagine, the doctors and dietitians at Mayo weren’t too happy about that. Fun factoid: The Cabbage Soup Diet makes similar weight loss claims to the Grapefruit Diet (lose 1. However, the origin of that diet isn’t as clear and there are no accompanying arguments that cabbage has special fat- burning powers. It is simply a very low calorie diet that can make you really gassy. Ewww. Science or myth? Have any clinical research studies evaluated grapefruit’s fat- burning enzyme potential? The answer to that is yes and no. Early studies did suggest that subjects on the grapefruit diet would lose weight, but this was most likely due to calorie restriction rather than any special fat- burning properties of the grapefruit itself. However, before we dismiss the claims of this diet completely, let’s take a closer look. After all, it’s possible that calorie restriction is not the only reason the diet helps people lose weight. Proponents of the diet could be in the right church but the wrong pew. Maybe they’re wrong about those magical fat- burning enzymes. But maybe grapefruit’s phytochemicals have an effect on weight loss, or maybe something in the fruit promotes satiety. Satiety and weight loss. Let’s look at satiety and weight loss first. A recent study evaluating the satiating effects of eating or drinking something low in calories before meals compared grapefruit, grapefruit juice, and water. The subjects lost weight, although not a lot. ![]() But it didn’t matter which of the pre- meal snacks they had (2). All had some small effect. However, a second study showed the opposite. ![]() ![]() Weight Loss Tips: Eat Eggs. Forget the egg and grapefruit diet, new research shows you could lose 2lb a month just by eating eggs for breakfast. The latest on how including grapefruit in your diet plan can boost weight loss. Trying to lose weight? Incorporate these healthy weight loss foods into your diet to burn more calories and shed pounds. ![]() ![]() ![]() Subjects who ate grapefruit lost more weight than those who ate a placebo (3). Makes you want to scratch your head and wonder, doesn’t it? However, overall it seems that eating any low calorie snack before a meal may help you eat less in total. Grapefruit itself isn’t the key. Grapefruit and phytochemicals. But what about grapefruit’s phytochemical content? Now we might be on to something. We know that phytochemicals (plant chemicals) are absolute superstars when it comes to decreasing our risk of contracting a host of chronic diseases. Citrus, and in particular, grapefruit, contains two of these superstars, flavonones called naringin and hesperidin. Studies conducted in mice and rats have confirmed that naringin and hesperidin act as antioxidants in the fight against free radicals, and reduce cholesterol and blood pressure. However, we can’t be as confident about these effects in humans. We’d need more studies with larger sample sizes to make that call. And at these high doses, we see even more evidence that phytochemicals lower cholesterol and blood pressure. Not only that, but in rats, wait for it. Remember, that study focused on rats who were fed a high dose of the concentrated phytochemical, not rats being served half a grapefruit before each meal. What to make of all this? Clearly more research is needed to see if the phytochemicals could be responsible for weight loss and other health benefits. Thank goodness researchers are a determined, inquisitive bunch, because this week’s research review builds on the best features of the previous studies in order to see if any clear answers to these ongoing questions can be found. Research question. This week’s research review aimed to determine if eating half a grapefruit before each meal decreases weight, blood pressure, or cholesterol levels. Dow, C. A., Going, S. B, Chow, H- H, S., Patil, B. S., Thomson, C. A. The effects of daily consumption of grapefruit on body weight, lipids, and blood pressure in healthy, overweight adults. Metabolism: Clinical and Experimental. Methods. This study used a randomized controlled design in which 7. The study timing corresponded to seasonal grapefruit crop production. The study lasted for a total of nine weeks: a three- week “washout” phase followed by a six- week diet intervention. An important note here on the study design is that it was not “blinded,” meaning that subjects knew which group they belonged to. Potentially, this could produce some bias. Keep that in mind when evaluating the results. Subjects. The researchers screened almost 3. Excluded from the study were smokers, post- menopausal women, individuals who had a co- morbidity like diabetes, high cholesterol, etc., those taking certain medications, those whose BMI (body mass index) was too high, and those whose weight was unstable. In other words, the researchers wanted “healthy” overweight individuals. During the washout diet phase, they lost a few participants, so they ended up with a total of 7. The control group included 2. Sometimes it’s more difficult to detect a significant difference in a healthy population, but based on some fancy statistical calculations, this sample size qualifies as large enough to determine meaningful differences between the control group and the test group, if any exist. Diet intervention. The first three weeks of the study was a “washout phase.” Participants followed a restricted diet to clear the body of any foods that might affect the study outcomes. Because this study was designed to determine whether or not there were active compounds in grapefruit that were responsible for potential health benefits, during the washout phase, participants were not allowed to eat any fruits or vegetables that were high in two classes of phytochemicals: polyphenols and carotenoids. Bummer – that meant no citrus, berries, spinach, carrots, tomatoes, sweet potatoes, grapes, kale, and so on. Yikes! I would have been one of those in the “discontinued trial because diet was too strict” category. After the washout, the 6- week intervention started. Both the control and the intervention group had to continue with the washout diet as their “background” diet, with the intervention group supplementing their diet with half a fresh Rio- Red grapefruit 1. How to eat a grapefruit. If you think this was self- explanatory think again. When it comes to research, attention to detail is the name of the game. Participants were given training on just how to eat said grapefruit half before each meal: peel it and eat all portions including the pith — the white part that you normally throw away. Participants were told to eat it because it contains vitamins, antioxidants and fibre. Also, they were not allowed to add sugar. Instead they used a zero- calorie sweetener. Measures. Researchers assessed a number of factors. Diet assessment – A registered dietitian collected data about the participants’ dietary intake via telephone using a method of repeat 2. The dietitian collected three recalls during the washout phase and three during the intervention phase and then averaged the reports. While dietary recalls may not provide the most accurate data, averaging a set of results rather than depending on one report alone would increase reliability. Compliance – Researchers gave participants a log book and asked them to keep a detailed record of each time they ate grapefruit during the six- week intervention. The researchers used a formula to analyze for compliance (number of grapefruit eaten before each meal/number of meals x 1. Bioactive content – To get an estimate of the amount of flavonoids in the grapefruits, the researchers took the average weight of 1. USDA Database for Flavonoid Content of Selected Foods. Anthropometry – Height, weight, waist and hip circumference and percent body fat of the participants were measured at baseline, week 6 and week 9. Weight Loss Benefits of Grapefruit Juice. The . Although fad diets are generally unhealthy and ineffective, one aspect of the grapefruit diet was on to something: Eating grapefruit or drinking grapefruit juice, as part of a healthy lifestyle, can help you lose weight. Grapefruit juice may help to lower insulin levels, which makes it easier to keep the pounds off. A study of 1. 00 men and women by the Scripps Clinic in San Diego, California, found that participants who drank grapefruit juice three times a day lost an average of 3. Some participants lost more than 1. Researchers believe 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. If you have high insulin levels and are already following a diet and exercise plan, adding grapefruit juice can help. Although juice is a more convenient way to get grapefruit into your diet, you may want to consider eating the whole fruit instead. In the Scripps Clinic study, those who ate half a grapefruit with each meal lost 0. Fruit juices in general contain a lot of sugar - - though grapefruit juice in particular isn't as sweet as other juices - - and lack the fiber found in the whole fruit, which may explain the increase in weight loss by the fruit eaters.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
September 2017
Categories |