Diet Drugs and Weight Control

Transcript: Compulsive Overeating, Dieting, Diet Drugs, Weight Control with obesity and weight control expert, Dr. Ben Krentzman. Eating Disorders. Expert information on anorexia, bulimia, compulsive overating. Eating disorders support groups, chat, journals, and eating disorders support lists.

Bob M: Our topic tonight is Diet Drugs and Weight Control. We get emails daily about the diet drug controversy and other weight control issues. That's why we've brought Dr. Ben Krentzman in to be our guest. Dr. Krentzman is an M.D. in California. He is an expert on the issue of weight control, obesity and diet drugs (eating disorder information). I believe his entire practice now consists of working with patients concerned about their weight. Dr. Krentzman also has an extensive internet site and we'll be giving you the URL at the end of the conference. Good Evening Dr. Krentzman. Can we start off by you telling us a bit about your expertise?

Dr Krentzman: Thanks Bob, For the last 23 years I have been interested in obesity. I switched from being a Board Certified Family Physician to only taking care of obesity patients in 1993. For the past 2 1/2 years I have maintained the largest website on obesity and have continued to research this subject. My Curriculum Vitae is online on my site.

Bob M: I'd like to start off by having you define "overweight" vs. "obese".

Dr Krentzman: Overweight is defined as being over 20% heavier than the Insurance companies Ideal Body Weight chart for your height and weight. Obesity is having too much fat on your body. You can be overweight and not obese if you are a weight lifter. The Body Mass Index (BMI) is a single scale used by obesity researchers as a measure of fat. It is a combination of height and weight to give one number. A BMI of 22 is considered about ideal. On the BMI scale the government says that 25 or above is overweight and 27+ is obese. The BMI does not measure fitness.

Bob M: What is the cause(s) then for being overweight vs. obese.

Dr Krentzman: Mostly people are overweight because they were born with the genetics which lead to being overweight. The genes are the program within our bodies that tell our brains how to operate. How we process food seems to be of little importance to obesity. There is an organ in the brain which regulates how much fat our body maintains. That organ is the hypothalamus and through a complex of neurotransmitters in the brain and the sympathetic nervous system, it closely regulates what we want to eat.

Bob M: So, if being overweight or obese is a function of genetics, what then is the point of dieting? (dangers of dieting)

Dr Krentzman: Since the success rate of long term weight maintenance is 2%, I do not see much point.

Bob M: Alright. Now I guess is as good a time as any to bring up the diet drugs. And I want to mention, before we get into it, that everyone here I imagine has heard the FDA warnings about taking fen-Phen and other diet drugs. It is very important that you check with your doctor before taking any weight control drugs.

Dr Krentzman: There is a tremendous amount of misunderstanding about the announcements in the press. The media has missed the point. The Mayo Clinic Press Conference on 7/8/97 was an announcement of a suspected condition (heart valve disease) which MIGHT be connected with obese women. At the press conference, a transcript of which is on my website, the doctor reading the message said that NO patient should stop their medicines without talking to their doctor. There is NO PROOF of any long term problems with the diet drugs as there has been only one article of a study longer than one year. All others are shorter.

Bob M: Are you saying, contrary to the FDA warning, that taking drugs like Fen-phen and Redux is safe?

Dr Krentzman: No, I am saying that the "Warning" is a routine way that the FDA asks all the doctors in the USA to be on the lookout for similar problems and to phone in with case reports when we find one. So far about 70 cases have been found out of the 8,000,000 users of diet drugs. Compare this with the 300,000 people who die each year from obesity related illnesses.

Bob M: Everybody has been so patient in the audience. I want to let a few audience questions on, then we'll continue with my questions. We are talking with Dr. Ben Krentzman. Dr. Krentzman is an expert in obesity and weight control. He has an extensive website on the subject and I'll be giving you his URL at the end of the conference.

Lady: I have never been to a conference, but I have a question... Why is it soooo much harder if you only have 20 pounds to lose than if you have 100 ?

Dr Krentzman: It is not harder. If you have, for instance, two people who are 5 foot 7 inches tall and one is 150 pounds and the other is 250 pounds then it takes more calories to keep the 250 pound person at that weight. Therefore they can burn more calories in a day than the more slender person can.

River: Whether or not there is proof, why would anyone want to create health problems in addition to their weight problem.

Dr Krentzman: The FDA asked our help in finding cases so they could get some idea if the diet drugs are somehow involved with heart valve illness. This has not yet been proven, only partly suggested. These may be the only 70 cases in all of time. Should this cause tens of thousands of obese people to die by avoiding the diet drugs WHICH WORK?

River: I understand your point. BUT my overweight is my only health problem (30 pounds) and although I've considered taking the drugs, I've decided against it because of the FDA warning. I guess the choice is the health problem I understand vs. the health problem I don't. Ultimately, it's a consumer choice.


Bob M: Can you please explain when it is appropriate to consider taking diet drugs like Fen-Phen and Redux?

Dr Krentzman: Anyone who has a BMI of 30 or more will benefit. Those with less weight (you can see a BMI chart on my website) can benefit if you are a BMI of 27 or more and have heart disease, diabetes or hypertension. Dr. Koop, former Surgeon General of the United States believes that Diabetics could benefit down to a BMI of 20 I will not help anyone lose weight below 20 because that is where lifespan begins to shorten.

Bob M: What is the difference between Fen Phen and Redux and what is each indicated for?

Dr Krentzman: Phen/Fen is made up of two separate drugs, Phentermine and Fenfluramine. Redux is made of one drug which is the active weight controlling half of Fenfluramine (Pondimin).

Bob M: But do both do the same thing? And what are the side effects of each?

Bob M: While Dr. Krentzman is answering that question, here's a couple of audience comments.

Rhonda S: I've been on redux a little over a week I have lost 4 lbs and I have trifold the energy I had before taking the drug. The only side effect I experienced was a horrible headache that lasted 4 days.

Lori H: I was on fen-phen for a few months and gained 15 pounds.

Dr Krentzman: Phen/Fen is made up of two separate drugs, Phentermine and Fenfluramine. Redux is made of one drug which is the active weight controlling half of Fenfluramine (Pondimin). In other words, fenfluramine and redux are the same. The side effects are identical. No one has ever given me any proof that my belief, loudly stated on my website, is wrong. The most common side effect is dry mouth (90%). Drowsiness occurs in about 40%. Less than 1% have diarrhea or constipation and even less have mental confusion or short term memory problems. All these side effects go away when the level of medicines is reduced or stopped.

Dr Krentzman: For the person who wondered why they could gain 15 pounds of Phen-Fen, The medication combination works on 60% of humans, and not on 40%. Since all other ways fall in the 2% success rate, the diet drugs are the best odds you can get. About 15 more medicines are in the research pipeline. See my site for details.

Bob M: I have heard, and you are the expert on this...Is it true that once you start taking these diet drugs that you shouldn't stop for the rest of your life?

Dr Krentzman: Yes Bob. IF you stop taking the medicines, there is a 98% chance that you will regain all the weight you lost over the next 5 years (or sooner). There was an article by a panel of obesity experts, called together by the National Institutes of Health to review the literature. They concluded that if you stop the medicines EVER you will regain ALL the weight you lost. (JAMA 18 Dec 1996). They said that using the medicines for less than 12 months had no value and that there was only one small study for over 12 months so they could not recommend using the diet drugs for longer. My study is 26 months along with 800 patients and no unusual problems. Another doctor here in Los Angeles says he has treated 20,000 patients in his 18 clinics without any strange problems. UCLA says they have treated 1000 without problems.

PEDSI: What good do these diet drugs do if you have to stay on them to prevent the weight coming back?

Dr Krentzman: What good does insulin do for a diabetic if they have to stay on it for life to prevent dying from diabetes? What good are eyedrops which prevent glaucoma from causing blindness? This is like asking an asthmatic to stop wheezing without taking their medicines. In all cases, including obesity, nothing is cured, only controlled. The diet drugs, if used a lot, could reduce that 300,000 deaths per year caused by obesity.

Mary33: Hi. I'm on a drug called Fastin (phentermine), what is the danger of it? I have recently lost 14 pounds in three weeks.

Dr Krentzman: No deaths have been reported associated with phentermine.

Bob M: If a person doesn't want to take drugs, what other ways, either dieting or surgical are there to lose weight?

Dr Krentzman: There are no other ways that work over the long term. Any time you reduce the total calories you take in, you will lose weight. The pills do this for 60% of the people who try them. Today I saw a 5 foot one inch lady who has lost from 150 lbs to 117. She went down to a size 3 and is now in maintenance. For those who are severely overweight, 40 BMI or greater, surgery has a 73% success rate. It is really worthwhile talking to someone who has done 100 or more of these operations. They work.

Liz: I am interested in drugs other than phen/fen and Redux. What other drugs are there out there and how effective are they when compared to Fen-Phen and Redux?

Dr Krentzman: There are a few drugs in the same classification as phentermine which are approved for use and do work. Phendimetrizine is one I use as an additional drug. It, and the others, are no more effective than phentermine, just different enough so that I can get around strange reactions and allergies. Fenfluramin and Redux and one other rarely used medication are in another classification with fewer alternatives. These drugs release the neurotransmitter serotonin. There are about 6 other classes of drugs which increase the serotonin in the brain. They are not more effective and are considered less effective.


Bob M: Many people, as you mentioned before, who diet, complain that keeping the pounds off is very tough. What is the correlation between taking the drugs and the need to exercise?

Dr Krentzman: There is very little use in moderate exercise. Since I am the only person who is trying the medicines without diet or exercise, and it works, this is an unstudied field. Moderate exercise can lower weight 5 or 10 pounds with diet. Then you must do this all the rest of your life.

Bob M: We are taking audience questions for Dr. Krentzman. If you're just joining us, Dr. Krentzman is an M.D. He's a nationally known weight control specialist and has written articles for professional journals as well as being interviewed as an expert on the subject by Time Magazine and I believe, he also recently appeared on the CBS newsmagazine, 48 hours, on their show on obesity.

Tina: Do your patients change their diet and exercise habits in addition to taking the drugs? Do they continue these changes after their weight loss?

Dr Krentzman: My patients sometimes change these habits. I ask all my patients to NOT DIET for the first 8 weeks. In this way I can tell if the medicines are working. If they diet, they WILL lose weight. But I won't be able to tell if the medicine helped. I tell my patients that exercise is good and very healthy and will help them to live longer.

Bob M: What about diet products like Herbal-life and herbs, etc. How effective are they?

Dr Krentzman: No better than dieting without them.

Bob M: To change the subject slightly for a moment. There have been articles recently tying obesity to depression. Can you address that?

Dr Krentzman: I have not seen any studies which show that the obese get more depressed than the thin. One big study by Stunkard gave psychological tests to 300 people before surgery and 600 random people (thin and fat). A year later they retested them and found both groups had the same amount of problems. The surgical group had lost an average of 60 pounds. Divorce, jobs, hospital admissions, illness, mental testing, all were the same. Obese people are not crazy. They are just obese.

Bob M: No. I am not saying they are crazy...and I don't consider being depressed as crazy, but I have heard overweight people say they are depressed and seen stories relating the two.

Bob M: Here's an audience comment on that subject...while we're waiting for Dr. Krentzman's reply.

Diana: Some depressives overeat while depressed, so it wouldn't be surprising.

River: Overweight people seem more unhappy, if only because we have such an image-conscious culture. It is depressing to be fat.

Dr Krentzman: I agree with River. Our culture has a lot of bigotry built in about being fat. I am saying that obese people get depressed with the same frequency as the nondepressed.

Geonurse: The Florida Board of Medicine just banned fen-phen for 90 days. What is your view on that?

Dr Krentzman: Yes, Geonurse, I believe that they have been pressured to do this and to allow those people succeeding in keeping weight off to go ahead and die. For the very overweight that is the alternative. Those 300,000 deaths per year loom large against the lack of the expected Primary Pulmonary Hypertension death increases. Today, I called a friend who is a pulmonary specialize in a 6 man group. He said he had never seen a case of PPH in his 25 years and neither had any of his partners. It is so rare, he never expects to see one. None of his literature tell of an increase in the number above normal. Where are all those dead bodies the media lead us to expect?

Bob M: Is there a different reason for obesity in men vs. women and are diet results different when it comes to the two groups?

Dr Krentzman: Not in my program. We have 60% success in both men and women. I cannot yet answer about reasons because there has been too little research in this area. Until recently obesity was a stigmatized condition and no real money or research was done. This is why my program of not dieting is a landmark. Strangely enough, no one else has done it.

Bob M: I just noticed that Dr. Krentzman has been with us for nearly 2 hours. So we are going to call it a night. I want to thank you Dr. for joining us tonight. There are many more questions the audience has, so I'm hoping that sometime in the next 2 mos. we can have you return. For more info you can visit Dr. Krentzman's very complete obesity/weight control website.

Bob M: Good Night.



APA Reference
Gluck, S. (2007, February 27). Diet Drugs and Weight Control, HealthyPlace. Retrieved on 2024, July 21 from

Last Updated: May 14, 2019

Medically reviewed by Harry Croft, MD

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