Posted by: Christopher Maloney, Naturopathic Doctor | July 23, 2012

Will Grapefruit Really Drop Eight Pounds Off Your Weight? The Grapefruit Diet Is Back, Again.

Grapefruit

Grapefruit (Photo credit: StudioGabe // Gabriel Li)

Anyone who remembers the 800 Calorie grapefruit diet should be puckering up and running from the room by this point.  But my checkout counter guru, the Women’s World, tells me that grapefruit is back.  No longer must you starve yourself.  Just eat grapefruit in addition to a regular diet, and the grapefruit itself will magically perform liposuction on you while you sleep.

So I went home and did a little digging.  I didn’t buy a bunch of grapefruit, because it’s the one citrus fruit I don’t like.  Seriously.  I’ll eat kumquats, limes, lemons, kiwi, etc.  but I don’t like grapefruit.  Maybe my liver knows it gets slowed down by grapefruit, I don’t know.

Unbelievably, we have  a human study on grapefruit and weight loss!  And it concluded:  “consumption of grapefruit daily for 6 weeks does not significantly decrease body weight, lipids, or blood pressure as compared with the control condition.”  Oops!  (Abstract below.)  But eating three halves of grapefruit a day did slightly better than not having fruit at all.

But wait, we have another study of grapefruit while people were already dieting.  In this case dieters had a preload of grapefruit, grapefruit juice, or water.  In all cases, having a preload helped the dieters lose weight.  Water did as well as grapefruit.

An earlier study did find that eating half a grapefruit did result in weight loss, but the authors did a variety of tests including using apple juice as a placebo.  In this study the grapefruit juice did almost as well as the grapefruit itself.  Average weight loss was 1.6 kg.

The article also cited a constituent of grapefruit as blocking insulin resistance, but it was based on the same research lab.  We’ve had the same research done in 2012, and the 2006 results weren’t replicated.

Can I just same that I am thrilled we have enough studies to say that, no, you can’t drop eight pounds from grapefruit.  It doesn’t hurt to have some, and you might even drop a pound or two.  But the grapefruit diet should stay as an historical artifact.

Metabolism. 2012 Jul;61(7):1026-35. Epub  2012 Feb 2.

The effects of daily consumption of grapefruit on body weight, lipids, and blood pressure in healthy, overweight adults.

Source

Department of Nutritional Sciences, University of Arizona, Tucson, AZ 85721, USA.

Abstract

Folklore has suggested that consuming grapefruit may promote weight control. Sparse data exist to support this hypothesis, although there is some evidence of health promotion effects with regard to blood pressure control and modulation of circulating lipids. The aim of this randomized controlled trial was to prospectively evaluate the role of grapefruit in reducing body weight and blood pressure and in promoting improvements in the lipid profile in overweight adults (N = 74). Following a 3-week washout diet low in bioactive-rich fruits and vegetables, participants were randomized to either the control diet (n = 32) or daily grapefruit (n = 42) in the amount of one half of a fresh Rio-Red grapefruit with each meal (3× daily) for 6 weeks. No differences between group in weight, blood pressure, or lipids were demonstrated. Grapefruit consumption was associated with modest weight loss (-0.61 ± 2.23 kg, P = .097), a significant reduction in waist circumference (-2.45 ± 0.60 cm, P = .0002), and a significant reduction in systolic blood pressure (-3.21 ± 10.13 mm Hg, P = .03) compared with baseline values. Improvements were observed in circulating lipids of those consuming grapefruit, with total cholesterol and low-density lipoprotein significantly decreasing by -11.7 mg/dL (P = .002) and -18.7 mg/dL (P < .001), respectively, compared with baseline values. This study suggests that consumption of grapefruit daily for 6 weeks does not significantly decrease body weight, lipids, or blood pressure as compared with the control condition. However, the improvements in blood pressure and lipids demonstrated in the intervention group suggest that grapefruit should be further evaluated in the context of obesity and cardiovascular disease prevention.

Copyright © 2012 Elsevier Inc. All rights reserved.

PMID: 22304836

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