You stay the same weight but you’d actually like to lose just a small amount. Not a lot, just a little – so that your excess fat just melts away without having to count calories. Researchers at Lund University in Sweden have made a discovery that might be of interest. They write in Nutrition Journal that you can boost the satiating effect of a meal by drinking a large cup of green tea at the same time.
Green tea & insulin
Green tea contains substances that enhance the effect of insulin. Epidemiological studies have shown that drinking green tea reduces the chance of developing diabetes-2 [Ann Intern Med. 2006 Apr 18; 144(8): 554-62.] and extracts of green tea boost sensitivity to insulin in human [Am J Clin Nutr. 2008 Mar;87(3):778-84.] and in-vitro studies.
The researchers at Lund University were curious whether they could achieve the same effects by getting people to drink a cup of green tea with meals, so they did an experiment with 15 subjects aged 22-35. The Swedes hoped that drinking green tea would make the glucose and insulin levels of the subjects rise less quickly than normal after a meal. If this were the case green tea could help reduce the likelihood of diabetes developing.
The researchers gave their subjects a meal consisting of white bread and turkey on two occasions. On one occasion the subjects drank a cup of hot water with the meal, on the other occasion a 300 ml cup of green tea. The researchers used Sencha tea, a green tea from Japan.
They brewed 9 g dried sencha leaves for three minutes in 300 ml water at 85 degrees. The result was a cup of tea containing 80 mg caffeine, 26 mg epicatechin [EC], 90 mg epicatechin gallate [ECG] and 32 mg epigallocatechin gallate [EGCG].
But the green tea had virtually no effect on the insulin or glucose levels, the Swedes discovered. It did inhibit the rise in the insulin and glucose levels, but the effect was not statistically significant.
What was statistically significant was the effect that green tea had on the feeling of satiety after the meal. This feeling was significantly higher ninety minutes after the meal. In addition, the subjects felt ‘fuller’ after drinking green tea with the meal.
This is an interesting discovery, according to the Swedes. If a bigger study using overweight subjects were to confirm these findings, then it may be possible to help fight fat by drinking green tea with meals.
Does green tea affect postprandial glucose, insulin and satiety in healthy subjects: a randomized controlled trial.
Results of epidemiological studies have suggested that consumption of green tea could lower the risk of type 2 diabetes. Intervention studies show that green tea may decrease blood glucose levels, and also increase satiety. This study was conducted to examine the postprandial effects of green tea on glucose levels, glycemic index, insulin levels and satiety in healthy individuals after the consumption of a meal including green tea.
The study was conducted on 14 healthy volunteers, with a crossover design. Participants were randomized to either 300 ml of green tea or water. This was consumed together with a breakfast consisting of white bread and sliced turkey. Blood samples were drawn at 0, 15, 30, 45, 60, 90, and 120 minutes. Participants completed several different satiety score scales at the same times.
Plasma glucose levels were higher 120 min after ingestion of the meal with green tea than after the ingestion of the meal with water. No significant differences were found in serum insulin levels, or the area under the curve for glucose or insulin. Subjects reported significantly higher satiety, having a less strong desire to eat their favorite food and finding it less pleasant to eat another mouthful of the same food after drinking green tea compared to water.
Green tea showed no glucose or insulin-lowering effect. However, increased satiety and fullness were reported by the participants after the consumption of green tea.
PMID: 21118565 [PubMed – indexed for MEDLINE] PMCID: PMC3002911