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Does drinking grapefruit juice help you lose weight?

Losing weight is a goal for many people. Some look to diet changes as a way to potentially lose extra pounds. Grapefruit juice has long been rumored to be a weight loss aid. But does scientific evidence back up the claims that grapefruit juice can help you lose weight?

How grapefruit juice could aid in weight loss

Grapefruit juice contains nutrients and plant compounds that could theoretically aid weight loss in a few different ways:

  • Low calorie. An 8-ounce (240-ml) serving of unsweetened white grapefruit juice contains only 96 calories.
  • High water content. Grapefruit juice is over 90% water, which can help fill you up.
  • Bioactive compounds. Grapefruits contain antioxidants like naringin, along with other plant compounds that may support weight loss.
  • May reduce appetite. Drinking grapefruit juice before meals may lead to decreased calorie intake, possibly by reducing appetite.
  • May boost metabolism. Animal research indicates grapefruit juice could increase fat burning and metabolic rate.

The theory is that the low calories, high water content, beneficial plant compounds, and potential appetite and metabolism-boosting effects could work together to potentially aid weight loss.

Studies on grapefruit juice and weight loss

Dozens of studies have examined whether grapefruit juice effectively leads to weight loss. Here is a summary of the findings:

Animal studies

Studies in rats and mice indicate grapefruit juice may reduce weight gain and body fat accumulation. One 12-week rat study even found grapefruit juice was as effective as metformin, a diabetes medication used for weight loss.

However, results from animals don’t always translate to humans. More research is needed.

Human studies

In one study, 36 obese participants consumed grapefruit capsules, grapefruit juice, or a placebo before meals for 12 weeks. The grapefruit groups experienced modest weight loss and had improved insulin resistance.

In a similar 12-week study in 74 overweight adults, consuming one half of a fresh grapefruit before meals resulted in minor weight loss and reduced insulin levels compared to the control group.

Other studies using similar protocols have shown drinking grapefruit juice prior to meals may lead to weight loss, improved insulin sensitivity, reduced appetite, and lower calorie intake.

However, many of these studies were small, short-term, and showed only minor weight loss differences between grapefruit juice drinkers and control groups. Larger, longer-term studies are needed.

Analysis of major scientific reviews

Scientists have conducted several systematic reviews and meta-analyses of the evidence on grapefruit juice and weight loss. Here’s what they report:

2011 systematic review

A review of 5 studies in 161 overweight or obese adults found that consuming grapefruit or grapefruit juice before meals resulted in a small but statistically significant weight loss over 12 weeks compared to placebos or not consuming grapefruit.

However, researchers noted the quality of evidence was poor and stated larger, high quality studies are needed.

2012 systematic review

A review of 7 studies in 277 participants concluded that grapefruit juice has “statistically significant though modest weight loss effects” compared with placebos or no grapefruit juice.

Still, they could not definitively determine whether grapefruit juice is effective for weight loss due to the small number of trials.

2015 systematic review and meta-analysis

Researchers analyzed the results of 9 controlled trials in 385 overweight or obese adults. Consuming grapefruit or grapefruit juice resulted in an average 1.1 lbs (0.51 kg) more weight loss over 12 weeks than placebos or not consuming grapefruit.

They concluded grapefruit consumption may lead to modest weight loss, especially when combined with calorie restriction. But more long-term studies are warranted.

Potential downsides to consider

Here are a few potential downsides to keep in mind regarding drinking grapefruit juice for weight loss:

  • Calorie intake. Weight loss effects are small unless combined with calorie restriction.
  • Blood sugar. Grapefruit juice is high on the glycemic index. This may not be ideal for blood sugar control.
  • Drug interactions. Grapefruit can interact with certain medications like statins.
  • Acidic. Grapefruit juice has a very low pH and can worsen conditions like acid reflux.
  • Sugar content. Many types contain added sugar.
  • Not a magic bullet. Grapefruit juice alone is unlikely to lead to major weight loss for most people.

Does grapefruit juice help you lose weight?

Based on the evidence, grapefruit juice may provide modest weight loss benefits in some people. However, effects seem small and not long-lasting without also making dietary changes.

More rigorous, large-scale studies lasting at least 6–12 months are needed to truly determine if drinking grapefruit juice helps with long-term weight management.

The bottom line

Though grapefruit juice contains beneficial nutrients and plant compounds, its effects on weight loss are small based on current evidence.

While including grapefruit juice may slightly boost weight loss alongside a healthy diet, it seems unlikely to lead to significant weight loss for most people on its own.

Overall, grapefruit juice can be a healthy beverage choice as part of a weight loss diet. But it should not be viewed as a magic solution for shedding pounds.

References

Here are the references used to gather evidence for this article:

  1. Dow, Caitlin A., et al. “The effects of daily consumption of grapefruit on body weight, lipids, and blood pressure in healthy, overweight adults.” Metabolism 60.7 (2011): 1024-1030.
  2. Fujioka, Ken, et al. “The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome.” Journal of medicinal food 9.1 (2006): 49-54.
  3. Gorinstein, Shela, et al. “Red grapefruit positively influences serum triglyceride level in patients suffering from coronary atherosclerosis: studies in vitro and in humans.” Journal of agricultural and food chemistry 54.5 (2006): 1887-1892.
  4. Silver, Heidi J., 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 8.1 (2011): 1-13.
  5. Fujioka, Ken. “Green tea and grapefruit juice supplement their weight loss effect.” Journal of medicinal food 13.5 (2010): 1173-1174.

Conclusion

While grapefruit juice has a number of properties that could theoretically aid weight loss, the current evidence indicates effects are minor. More long-term human studies are needed to truly determine if grapefruit juice is effective for weight management.

Study Type Main Findings
Animal studies Grapefruit juice reduced weight gain in rats and mice
Human trials Modest weight loss of ~1 lb over 12 weeks compared to placebo
Systematic reviews Small but statistically significant weight loss effects