Why are my efforts at portion control failing?

Q. I realize that my food portion sizes are my biggest obstacle to losing weight. But whenever I try to cut back, I seem to just eat more later. How can I tackle this?

A. Congratulations for recognizing and being ready to tackle an important obstacle between you and better health!

First, try to identify why your previous efforts to reduce portions have not worked out. When you eat more after having reduced portions, are you hungry? This is a key question, so I urge you to keep a record for a week or so, whether on paper or your computer. Perhaps you have cut back too much. You might try reducing your usual portion by just a quarter, or even less.

Another key to success is that you need enough bulky, low-calorie foods to fill up on. Make sure you include some simple raw vegetables, salad, vegetable soup, stir-fried vegetables or fruit in your meals as you cut back on the high-calorie foods.

On the other hand, perhaps you'll find that the urge to eat more is not due to hunger. Perhaps you need to drink more fluid?

Perhaps you are facing some emotional fear or feeling of deprivation when you cut back. This is especially common among people who have used very restrictive diets in the past, and those feelings need to be addressed. Simply keeping a record of what is going on with this urge to eat more will probably not immediately change your eating, so don't let this make you feel guilty.

Understanding the problem is the key to finding a solution. If hunger is the issue and you have trouble pulling together meals that work better for you, I urge you to find a registered dietitian (RD) in your area who can help you with fresh ideas. If fear of deprivation or other emotional issues seem to be the problem for you, some dietitians are trained to deal with emotional "disordered" eating patterns, too; otherwise a mental health counselor with training in the field can help you work through and beyond these issues. Don't give up.

Q. Is it true that pomegranate juice is like grapefruit juice regarding interactions with medications?

A. We need more research to be sure, but it looks like any effect of pomegranate juice on the body's metabolism of medications is not as significant as that of grapefruit juice.

Liver enzymes that metabolize a variety of medicines are inhibited by grapefruit juice, which results in higher blood levels of these drugs and thus potential side effects.

For example, levels of several statin medications to lower blood cholesterol can increase and lead to muscle weakness or aches and perhaps even kidney damage; increased levels of certain other medicines can also occur and lead to side effects.

Initial test tube and animal studies suggested that pomegranate juice might also inhibit these enzymes and produce similar effects.

In the only human controlled study I can find, pomegranate juice showed absence of effect similar to water, while grapefruit juice showed its usual effects. However, there has been one case reported with a significant interaction.

Since individuals may vary in their sensitivity, if you drink pomegranate juice every day and take medications, tell your doctor so that this can be considered as your medicine's effectiveness is monitored.

While there doesn't seem to be reason at this time to avoid pomegranate juice due to food-drug interaction, remember that, like all juices, it is concentrated in calories. So unless you need large amounts of concentrated calories, don't let news of pomegranate juice's high antioxidant content lead you to consume large amounts daily or you may face unhealthy weight gain.

• Provided by the American Institute for Cancer Research. More about the group and its New American Plate program at aicr.org.