A couple of interesting studies have come to light discussing the potential of grapefruit on weight and insulin resistance (diabetes risk). The first study I’ll talk about is an animal study done in mice.
The researchers took two groups of mice and fed one group sweetened water, and the other grapefruit juice (1). These mice were on a high-fat diet to promote weight gain (mice gain a lot of weight on a high-fat diet, this does not hold true for humans when the fat comes from the right sources). What they found was pretty remarkable, the grapefruit juice fed mice ended up weighing 18% less, having 13-17% decreases fasting blood sugar, a 3-fold decrease in fasting serum insulin and a 38% decrease in liver triacylglycerol values!
The researchers stated that the grapefruit juice exhibited a similar effect as the anti-diabetic drug Metformin. So this simple addition to their diet had a huge effect!
But what about grapefruit in humans? Well, a recent study sought to find that out as well (2), they separated 91 obese patients into 4 different groups, (a).Apple juice, (b) Grapefruit capsules, (c) Grapefruit juice (d) half a fresh grapefruit. They studied them for 12 weeks and took measurements before and after the experiment.
After 12 weeks of the trial, the biggest effect was found from the group eating the fresh grapefruit, with a 1.6kg (3.5lbs) weight loss, followed by the grapefruit juice group with a 1.5kg (3.3lbs). The grapefruit capsules group lost 1.1kg (2.4lbs), whereas the apple juice didn’t lose any significant amount.
What’s more, there was a significant reduction of 2-hr glucose levels in the grapefruit groups compared to the apple juice group. The biggest difference was from the half grapefruit eaten before meals.
So the take away here is to eat half a grapefruit before each meal or failing that, a glass of grapefruit juice. Try it for a week and see what effects this has on your blood sugar. You may be surprised by what happens!
Just a heads up though, grapefruit juice can interfere with some common drugs, so talk to your doctor before trying this out if you’re on any prescriptions.