Make Your Diet More Effective with A Little Something Before Meals

There are all sorts of appetite reduction tips that we hear from our patients. Some swear by chewing gum to reduce their appetite, although at least one study indicates that it doesn't actually affect appetite. People also talk about having a glass of water before meals, and in one study it did seem that having two cups of water before meals helped people lose more weight. On the other hand, it may not be the water that's making the difference: in another study, those who had soup as a first course ate 20% less of the entree that followed.

Researchers at Vanderbilt University designed a study to see if having something to eat or drink shortly before a meal (a "preload") would affect weight loss (Nutr & Met 2011;8:8). They decided to compare a fruit, a fruit juice, and water, and chose grapefruit and grapefruit juice as their test items. (Grapefruit was chosen because of its high antioxidant levels and high water content.)

Sixty-four otherwise healthy men and women were recruited to participate in the study. At the start of the study the researchers assessed the participants' height, weight, demographic and dietary information along with cholesterol tests. For the next two weeks participants followed a prescribed diet plan that reduced their daily calories by 12.5% from their customary individual daily intake. At the close of the second week they were again weighed and their cholesterol was again tested.

For the following 12 weeks the participants continued their prescribed diets, with the addition of one of three randomly assigned preloads before every meal: half a grapefruit, a pre-measured amount of grapefruit juice (containing the same number of calories, water and vitamins as the fruit), or a pre-measured amount of water of the same amount as the grapefruit juice.

Both groups, however, continued to eat the same reduced number of calories. The grapefruit and grapefruit juice groups had their overall diets adjusted to allow for the additional calories the fruit and juice added to their diet. On the other hand, those who were assigned to having water before meals were assigned fruit to have between meals, as snacks, so that they were still ingesting the correct number of calories.

The researchers found that members of all three groups lost weight more quickly during the period in which they had a little something before their meal than they had during the initial two-week period without those preloads - about 13% faster, on average. Why? According to the participants' dietary records, they were spontaneously eating less. What's really interesting, however, is that regardless of which preload the participants were assigned, they still indicated about the same level of hunger and satisfaction after meals.

Overall, all three groups lost about the same percentage of their overall body weight: about 7%.

What this means for you

Keep in mind that all three groups continued on a prescribed diet of 12.5% fewer calories than they were used to - including the calories contained in the grapefruit or grapefruit juice. Rather than tracking the calories in a preload of fruit or fruit juice for your diet, try drinking a glass of water about 20 minutes before dinner. As part of an overall weight loss strategy, it does appear that consuming water before meals may help you lose weight - because you'll want to eat less.

First posted: August 31, 2011