Dr. Walter Willett is Professor of Epidemiology and Nutrition and Chairman of the Department of Nutrition at the Harvard School of Public Health and Professor of Medicine at Harvard Medical School. He grew up in Madison, Wisconsin, studied food science at Michigan State University, and graduated from the University of Michigan Medical School before obtaining a Doctorate in Public Health from the Harvard School of Public Health. Dr. Willett has focused much of his work over the last 25 years on the development of methods, using both questionnaire and biochemical approaches, to study the effects of diet on the occurrence of major diseases. He first applied these methods in 1980 in the Nurses' Health Study I, a cohort of over 121,000 female registered nurses 30-55 years of age who have completed biannual mailed questionnaires about known or suspected risk for cancer and cardiovascular disease. He is Principal Investigator of the Nurses' Health Study II, a prospective cohort investigation established in 1989 with over 116,000 younger female registered nurses. This study is also designed to examine the association between lifestyle and nutritional factors and the occurrence of breast cancer and other major illnesses.

In addition to his work with the Nurses' Health Studies I and II, Dr. Willett initiated in 1986 a parallel prospective study of diet in relation to cancer and cardiovascular disease among 52,000 men, the Health Professionals Follow-up Study. He has published over 800 articles, primarily on lifestyle risk factors for heart disease and cancer, and has written the textbook, Nutritional Epidemiology, 2nd edition, published by Oxford University Press. His recent book for the general public, Eat, Drink and Be Healthy: The Harvard Medical School Guide to Healthy Eating has appeared on most major best seller lists. Dr. Willett is a member of the Institute of Medicine, National Academy of Sciences.

On behalf of Dr. Willett, Esther Kim, a graduate student in Walter Willett's nutrition program at the Harvard School of Public Health will answer your questions.

Esther Kim obtained her Bachelor's in Science and Nutrition from Cornell University and her Master's in Science in Nutrition from Tufts University. Presently, she is pursuing her Doctorate in Nutritional Epidemiology at the Harvard School of Public Health and is currently in her third year. In addition, she has been a Registered Dietitian for over five years, and is also a Licensed Dietitian in the state of Massachusetts. She has specialized in oncology nutrition at New England Medical Center in Boston, Massachusetts, and in Medical Nutrition Therapy at Brigham and Women's Hospital in Boston, Massachusetts. She currently works part time as the Health Educator and Registered Dietitian at Be Well! at Beth Israel Deaconess Medical Center in Boston, Massachusetts. She provides educational programs for successful weight management. In addition, she is developing nutrition education programs for patients before and after bariatric surgery (gastric bypass surgery) as part of a comphrehensive program involving exercise and behavioral management. This year she received the Oncology Distinguished Practice Award from the Oncology Nutrition Dietetics Practice Group of the American Dietetics Association.

Steve asks:
Hi, will you comment on the pros and cons of taking fish oil to get omega 3 fatty acids? How are Omega 3 fatty acids different from other fats?
Thank you.

Kim's response:
There are many advantages to taking fish oil supplements to obtain omega 3 fatty acids. However, there are also some precautions you need to consider before taking these supplements. Omega 3 fatty acids are a type of polyunsaturated fatty acids found in high amounts in fish. Recent research has indicated benefits of omega 3 fatty acids in protection for heart disease, as well as secondary prevention for those who have previously had heart disease. Fish oil supplements are an easy way to obtain the benefits of omega 3 fatty acids, however, it is not for everyone. Fish oil supplements may prevent your blood from clotting rapidly and is not advise for someone with a blood clotting disorder, or those on anticoagulant therapies. In addition, there could be potential for contaminants such as mercury to be found in the supplements, even though this is unlikely. To take advantage of the heart healthy benefits of omega 3 fatty acids, and also as a good source of protein, the American Heart Association currently recommends that adults eat at least 2 servings of fish each week. However if you do consider taking fish oil supplements, make sure to check with your doctor first.

Greg asks:
It seems difficult to find good sources of soluble fiber. The only sources I see recommended with any frequency are psyllium, which is not a common ingredient, and fruits, which have a high glycemic index. Can you recommend any common foods with significant levels of soluble fiber that have a lower glycemic index level?

Kim's response:
Many foods such as legumes, oatmeal and fruits and vegetables contain high amounts of soluble fiber, as well as being low in glycemic index. These foods include kidney beans and pinto beans, and Brussels sprout which each has 2 grams of soluble fiber per cup. Another great source are prunes, which contains 3 grams of soluble fiber per 6 medium prunes. Half a medium grapefruit and 1/3 cup of uncooked old fashioned oatmeal also contains 1.2 grams of soluble fiber, and is low in glycemic index.

Bobby asks:
After watching the Scientific America special on diets, I found your approach very interesting and will be buying your book this weekend. My question pertains to the new weight loss pill Trim Spa. When I asked my doctor she was not sure about it because it is still fairly new. I am a 27-year-old male. I am 6'4" and weigh 320lbs and climbing. I need to get a handle on my weight problem immediately. I have considered this drug now that there is an ephedra free pill. I understand that there are always risks when taking drugs, but the health risks due to my weight are very concerning to me as well. I am considering following your diet suggestions and taking this pill to jumpstart the process. Is that OK or do you have another suggestion. Thank you for your time.

Kim's response:
That is great that you are motivated to modify your eating habits. In regards to Trim Spa however, the ingredients ranging from cocoa extract to vanadium have had limited studies or in some cases, no studies have yet been conducted in humans to research its effect on weight loss or to increase metabolism. In addition, since dietary supplements are not regulated in the US, it may be possible that you may not be getting the correct amounts of each ingredient as stated, or the dosages may be too low to have a benefit even if some of the ingredients have a limited advantage on weight loss. The best way to jump start your metabolism, along with the healthy approach to eating we have described is to start an exercise plan involving both cardiovascular activity as well as strength training.

Jude asks:
I have friends who have been on Weight watchers flexpoints and have lost a lot of weight. I am a diabetic and I am unclear whether a diet like this would work for me.

I am concerned that I am not aware how using this points system I can track my sugar or even what my total number of sugars should be for a day.

In some reading I have done I think I might need to review the glycemic index associate with fruits, breads etc. and look for those in the low or medium category while still tracking to the point based weight loss plan.

Any clarification you can provide would be great, I haven't found any diet other than the exchange diet geared towards blood sugar management, frankly I am just looking for something easy and the points seem easy I just need some clarification. Thanks- Jude

Kim's response:
The Weight watchers flexpoint system is a relatively easy tool to help participants lose weight, however, as you mentioned, additional caution needs to be taken if you are diabetic. Unfortunately, using the flexpoint system and watching only for high glycemic index foods may not be an appropriate option for you since you need to take your complete diet into account, balancing carbohydrates, protein and fat. It is important to consult with your doctor, as well as a registered dietitian about finding an appropriate diet to manage both your blood sugar and help you lose weight.

Dawn asks:
What can I do to lower my LDL? My total cholesterol has gone up from last year from 195-215 today. My HDL is 64 & LDL is 126. I am a 58 yr. female, 5'5' med. frame & 140 lbs & exercise daily, including yoga, wt training, walking, and an aerobics class.

Kim's response:
You are off to a great start with your exercise plan! And your LDL is really not bad, especially in light of your high HDL. Some dietary modifications to help lower your LDL include decreasing saturated fats found mostly in animal products such as red meats and whole milk and cheeses, as well as trans unsaturated fat found in vegetable shortening such as Crisco, and many margarines and a large number of processed foods - look for partially hydrogenated oils in the ingredient list. Instead, substitute them for monounsaturated fats found in abundance in olive oil, canola oil and most nuts, as well as polyunsaturated fats found in corn oil, soybean oil and in fish.

Nazia asks:
What are you views about the South Beach Diet?

Kim's response:
The South Beach diet, as with many other fad diets can be an effective tool for weight loss because of reduction in refined carbohydrates and caloric restriction. The South Beach diet does emphasize the importance of healthy monounsaturated and polyunsaturated fats, which is good. However, some concerns with the South Beach diet are a ban on a large number of fruits and whole grain products. Avoiding these foods may mean missing out on important vitamins, minerals and phytochemicals, whereas some can be used in moderation. In addition, animal and dairy proteins are prominent instead of healthier vegetable protein alternatives. Furthermore, the South Beach diet does not emphasize the importance of exercise as part of a healthy lifestyle to help successfully lose weight and more importantly, keep the weight off.

Tom asks:
Do you believe it is beneficial to take dietary supplements like vitamins? If so what do you recommend for a 58-year-old male? Thank you

Kim's response:
For most adults, a daily multivitamin with minerals is a good insurance policy for your health. Previously, vitamins were primarily considered to prevent deficiencies. However, emerging evidence suggests the benefits of larger doses than the minimum needed to prevent deficiency, may be valuable for your health. Some of these vitamins include folic acid for heart disease and colon and breast cancer, and Vitamin D for bone health and to reduce the risk of fractures. Nevertheless, a multivitamin cannot compensate for an unhealthy diet. In addition, as with all supplements, it is good to discuss this with your doctor.

N.L.Glass asks:
I would like to ask two questions? What do you think about the south beach diet for people with Syndrome X and should you limit protein intake? Thank You, N.Glass

Kim's response:
Syndrome X, as defined in the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults, by the presence of three or more of these characteristics including abdominal obesity, elevated triglycerides, low HDL cholesterol, insulin resistance, and high blood pressure. The South Beach diet although it focuses on low glycemic index foods and monounsaturated fats instead of saturated fats, may not be the best option for a person with Syndrome X. Fruits and vegetables in abundance (but beware of all the calories in fruit juice) are important for a healthy diet to help decrease blood pressure, and lower risk of heart disease. In addition, protein intake does not need to be limited, however an emphasis on vegetable protein instead of animal protein is recommended.

Jill asks:
Are calories from all vegetables good? I like beans (dry and then rehydrated in soups) but heard that their high carb content is bad for you and helps you gain weight. Does it matter if I eat grapes over oranges or watermelon or should I worry about the sugar content? Thanks.

Kim's response:
Beans are a good source of protein as well as fiber and may actually help you lose weight because they are lower in calories compared to most animal proteins, as well as being tasty and satiating. Also, all vegetables are good - make sure to eat a variety and focus on vegetables rich in color, green, orange and red (but don't increase potatoes). In addition, grapes, oranges and watermelon are all great to eat in moderation, however it is possible to overdo any good thing. In addition, watch out for fruit juices since it is very easy to over consume calories this way.

Melinda asks:
Do you think that food and/or sugar is just as addictive as alcohol?

Kim's response:
We have a strong drive to eat, however, specific foods are not as addictive as alcohol.

Jennifer asks:
I have a weight loss question.

First, please allow me to provide a few details about myself, which may aid you in answering my question. I'm female, 27 years old, a non-smoker. I'm 5'4" and currently weigh 178 lbs. My BMI is 29.8. Two years ago, I weighed about 210 lbs. I went on the Body for Life Plan (Bill Philips) and I lost about 40 lbs in 6 months. I got as low as 168 lbs and then just stopped. I tried changing routine, eating more, eating less, but the scales wouldn't budge. Since then I've gained 10 lbs back and I tend to rise and fall within the same 5 lb range, so I seem to be maintaining fairly well -- I'm not gaining it all back. I am wondering why I cannot lose weight. I've had glucose tolerance tests done, hormones, insulin, full blood and hormone workup -- for all intensive purposes I'm "normal". I'm averaging about 1500 calories/day. Sometimes a little less, sometimes a little more. I do karate twice a week for two hours and I run/walk three days a week for 30 minutes -- Still no change in weight. I know that there is fat to lose because my adipose tissue is quite pronounced.

MY QUESTION: Do you have any suggestions as to why I can't lose weight and/or what might help me lose weight? Many thanks for your assistance.

Sincerely, Jennifer GrosLouis Canada

Kim's response:
Congratulations in maintaining a major weight loss - you should feel great about this accomplishment. Many people find that they require more physical activity and may benefit from 60 minutes each day to control their weight. You will need to be creative about building this amount of activity into your life - there are a thousand different ways to do it. In addition, both cardiovascular activities as well as strength training are essential for weight loss.