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Podcast: What everyone needs to know about obesity

Feb 6, 2023

Mitchell Roslin, MD, joins the 20-Minute Health Talk podcast to break down the factors that contribute to obesity

There are many misconceptions around weight — starting with the fact that people burn fat differently depending on their size, says Mitchell Roslin, MD, director of bariatric surgery at Lenox Hill and Northern Westchester hospitals. On this episode, he breaks down the factors that contribute to obesity, from genetics and lifestyle to the way our bodies convert food into energy.

Obesity itself has an impact on one's ability to lose weight due to something he calls the "metabolic switch." Dr. Roslin explains how weight gain is linked to other illnesses like cancer and when people should consider talking to their doctor about medical weight loss strategies, such as medications and weight loss surgery

Dr. Roslin is a pioneer in the field of bariatric surgery, helping to develop advanced treatments like the single-anastomosis duodenal-switch, also known as SADI.

Podcast transcript

Rob Hoell (Host): 00:30    
More than 70 percent of adults age 20 or older in the US are overweight or obese. Is this a problem that's getting worse, or is this a problem that we're starting to get a handle on? 

Joining me today to answer those questions and more is Dr. Mitchell Roslin. He is the director of Bariatric Surgery at Lenox Hill and Northern Westchester Hospitals. Welcome to 20-Minute Health Talk.

Mitchell Roslin, MD: 00:51    
Rob, thank you for having me. 

Host: 00:53    
How do people become obese? 

Dr. Roslin: 01:00    
It is a very complicated story. Obesity actually means excess fat and despite advances in medicine, we now have more people living with chronic diseases at a younger age. That probably has to do with the change in our food supply, where we get our meals from, and what we are eating. Eighty-five percent of our population has some evidence of metabolic disease. Sixty percent are overweight. In many places, more than 40 percent are obese. What I concentrate on is the morbidly obese, or obesity that is likely to cause a reduction in life span; a significant reduction of ten to 15 years. It is up to between eight and ten percent of the population. 

Host: 01:52    
We know that severe obesity, which is defined as having a body mass index of 40 or higher, can shorten life span. Why is that? 

Dr. Roslin: 02:00
Think of obesity as kind of like the furnace being on. It is a metabolic disease where basically you have increased glucose turnover and increased insulin turnover. When people are obese their metabolic rate is high. What happens when they try to lose weight? That opposes the weight loss because their metabolism slows down. 

It also tells you that people who are obese do not have a slow metabolism. The furnace is on. What happens if you leave the pump on your house always on? What happens if the car has more miles? It wears out sooner. When you get up to severe obesity, people lose between ten and 15 years of life expectancy. 

Obesity and cancer

Host: 03:01
We also know there is a correlation between obesity and some types of cancers. How concerning is that?

Dr. Roslin: 03:09
We tend to think of obesity as a lifestyle choice or lack of willpower, which is wrong. We think of cancer as bad luck. If you look at the risk of cancer death and obesity, they superimpose. I always like to talk about the state of Louisiana. Louisiana has the fourth-highest obesity rate and fourth-highest mortality from cancer deaths. Cancer has become much more prevalent as obesity has risen. 

There are now 13 cancers that have been strongly associated with obesity. Now whether obesity is the cause, or it is kind of the kerosene on top of the fire because the same things that happen in obesity, like high glucose, higher insulin rates, higher insulin-derived growth factor, they may just be feeding and creating a perfect nutritional environment for the tumor. People who are obese who do have cancer, tend to present at a higher stage and tend to be harder to treat. 

Host: 04:10
Yeah. I think in one of the talks that you gave, you mentioned how you do not really see cancer in muscles. Right? The heart does not get cancer. 

Dr. Roslin: 04:19
We would tend to think that cancer is random chance. Where there is a lot of activity, like in the heart cancer is very, very rare; muscle is rare as well. It seems that the more metabolic active parts of the body have managed to arrange safety mechanisms to allow them to have this high energy turnover. That is kind of what happens in cancer. Basically, the definition of cancer is unrestrained growth. Cancer cells do not need oxygen and blood supply to grow very well. They will get what they need just with glucose. 

"There really is only one way to treat obesity, and that is a healthy lifestyle. The question is, what tools are we going to give you so that the thermostat, the brain, and your body match?"

- Mitchell Roslin, MD

What causes obesity?

Host: 05:03
What factors contribute to obesity?

Dr. Roslin: 05:11
The biggest risk factor of obesity, like everything else, is somewhat genetic. You cannot change your genes. What you inherit is the likelihood. Obviously, lifestyle is really important. I tell every patient that I cannot out-operate a poor lifestyle. Stated differently, I am not making the potato chip healthier. I am changing your body around so that hopefully you will eat less and be full faster. There really is only one way to treat obesity, and that is a healthy lifestyle. The question is, what tools are we going to give you so that the thermostat, the brain, and your body match? 

The problem with obesity is that the thermostat is miss set. A switch is turned on, which encourages you to store fat and not burn fat. That explains why when heavy people exercise, they are hungry, and they eat more. It limits any weight loss. When they reduce their calories, the body responds by making them hungrier, and it becomes more efficient and imposes weight loss. A switch is turned on. The best way to turn it off is going to be medications and/or surgery combined with working on lifestyle adaptation. It is not one or the other. It is using one to help the other. 

What is the metabolic switch?

Host: 06:44
When you talk about a switch, what exactly do you mean?

Dr. Roslin: 06:52
What I think happens in the body is we have adapted mechanisms that allow us to live when food was plentiful and food was scarce. What happens in the body is that today’s processed foods are basically sending the message to the brain that food is going to be scarce and that we need to build up our fat stores. 

Instead of having that message seasonally like a bear would have before it is hibernating, we are getting that message chronically. That is telling us to store fat for impending problems that are coming on. Then what happens is you also develop an inflammatory response because this is not inert. It keeps on going on. 

Essentially as patients age, they begin to lose cellular function, and they actually lose the ability to metabolize fat. If you are not burning fat, you have to eat more carbohydrates. It explains why once people get obese, there is the drive to continuously eat. It is not willpower. If they did not do that they would fall on the floor. 

Host: 08:44    
Yeah. What you are saying is basically somebody who is obese and somebody who is a good weight, they can do the exact same thing, eat the exact same food, and have the exact same day. One is burning less fat than the other. 

Dr. Roslin: 08:55    
When you go into a restaurant, you are seeing how many potential calories the food is. You are not seeing internally how you process that fuel and how you burn that fuel. That is where we are all different. 

I see patients who say, "I am going to the gym five times a week. I have changed my diet completely, and I cannot lose a pound." The answer is yes. Once they reach a certain point, that is entirely possible. Then when you calorically restrict them, they will lose a nominal amount of weight. As soon as they eat slightly more, they bounce right back. It is a very complicated system and equation. It is also very different for people. We have done people a disservice by not understanding this really well. 


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How is obesity measured?

Host: 10:03    
How do you measure obesity then? 

Dr. Roslin: 10:05    
We measure obesity by putting your height and weight together into a number called body mass index (BMI).

  • A BMI around 25 is normal
  • A BMI of 30-35 as defined as obese
  • A BMI of 35 or higher is defined as severe obesity

That is how we generally measure obesity. As we go forward and we evolve as a field, we need more equipment than just a scale, because this does not take into account body composition and we should. 

When you lose weight, the goal should be to lose fat tissue, not lose lean body mass which is basically your muscle and bone. The truth is, when you lose weight, you lose a combination of all three of those things. Kind of what our whole focus here at Northwell and with my team is to try to encourage you to lose the most fat while not losing muscle and bone. 

Host: 11:02    
Easier said than done. 

Dr. Roslin: 11:04    
You need to eat the right foods, not starvation. If you have gut-altering surgery, you may need to be on supplements. You need to do a degree of resistance training. Again, as you and I both get older Rob, we lose muscle and bone. The body’s metabolism slows down. As you get older, you are losing mitochondrial function which is the part of the cell that burns fat. Therefore, the importance of lifestyle really becomes more significant.

Host: 11:55    
When you say eat the right foods, what do you mean? What are the right foods to eat? 

Dr. Roslin: 12:00    
Number one, I think the healthiest diet is one-third a protein source. Say chicken, fish, eggs, and beef – lighter is probably the better. The more farm-raised the better. Two-thirds of foods that have fiber in it, like green vegetables, cauliflower, and legumes. You want to limit your starch intake. Essentially, if it comes out of a package or does not spoil, stay away from it unless it is almonds or nuts. If you never went into the middle of the supermarket, you would be absolutely fine. If you only put your food in a refrigerator, you would be way better off. 

We have spent so much time confusing people with fat-free and carbohydrates. Go back to a diet where things grew in the ground or where protein sources have one-third of a protein source and two-thirds of a source that is high in fiber. That is going to be the healthiest diet. Fiber is really important to keep your gut healthy. Foods that have fiber tend to be, as I said, green vegetables, legumes, and cauliflower. 

Medical weight loss: When to see a doctor

Host: 13:19    
When should people talk to a doctor about their weight? 

Dr. Roslin: 13:34    
Excellent question. First of all, my first answer is that I think it is really important that we begin treating people with obesity. Medical weight loss treatment does not necessarily mean medications or surgery. Assessing metabolic disease, looking at insulin levels, looking at even subtle things like fatty liver and infertility early on. The earlier in the process, chances are the less invasive treatments are going to be more effective. This is whether that is behavior modifications, then pharmaceuticals, to the new drugs like Ozempic, Mounjaro, and the new drugs that are coming to bariatric surgery. 

I think we are going to go through a transition where the idea is, by more aggressively treating this we can limit the chronic diseases that we are seeing like heart disease, diabetessleep apnea, and dementia on the other side. Keep people off medications for those types of areas. When we talk about who should seriously consider bariatric surgery, it's people who:

  • Have higher body mass indexes
  • Sleep with sleep machines
  • Have cardiovascular disease
  • Have orthopedic impairment
  • Have diabetes and are on insulin

What is weight loss surgery?

Host: 14:56
What exactly is weight loss surgery and how effective is it really?

Dr. Roslin: 15:11
People like myself can manipulate the stomach and the intestine. We can either make the stomach smaller so that you get full faster, but it is not all mechanical. When we actually take certain parts of the stomach out, we are changing some of the hormones that drive hunger. We can bypass parts of the intestine. When we do that, we actually encourage the release of certain hormones that are made in the intestine that stimulate satiety. When you actually speak to patients, they are enormously happy by and large. You think, that is because they have lost weight so the ends justify the means. 

Something else is happening when bariatric surgery is well-calibrated. Their desires, their brain, and their GI tract match. Think about this: a baby does not need to be told to stop eating. Babies do not eat all the breastmilk at one time; they stops eating on their own. There is a balance between the brain and the thermostat, taking in the adequate energy needs that go astray. Bariatric surgery is the best way that we have right now of restoring that balance. That is what I think gets lost a lot of times in the conversation. 

Host: 16:26
You are fixing the thermostat. 

Dr. Roslin: 16:28
You are fixing the thermostat. You are making the desires and the temptations match the GI tract. As a result, that can lead to a positive lifestyle. Not to mention, the cognitive impairment that people have with metabolic disease, sleep apnea, and obesity. The truth is, everything in the body is holistic and everything goes together. What you eat and how it affects your body is more than weight. Weight may even be a marker of everything else that is going on, but it affects your brain. It affects your liver. It affects your reproductive system. There is no way to treat things. The idea that you are healthy, but is something we kind of have to abandon.

Host: 17:14
Are there psychological benefits to weight loss surgery?

Dr. Roslin: 17:22    
Especially for the first year. Sometimes there is the tendency to think that everything in your life is weight related. Not everything is due to your weight and your ability. 

There is certainly a honeymoon period of time like everything else. There is no one answer that is true of anything. 

Host: 17:33    
Does the surgery extend life? 

Dr. Roslin: 17:35    
Absolutely. There is data on that. Certainly, for people that have advanced metabolic disease, their life expectancy can be reversed by ten to 20 years. 

Host: 17:41    

Dr. Roslin: 17:42    
Those patients, from a research standpoint, would be the easiest to show an advantage for. 

Host: 17:46    
Wow. You are also a pioneer of a different type of weight loss surgery. Tell me a little bit about that. 

Dr. Roslin: 17:52    
When I came into this field, it was the era of gastric bypass, participated in the care of famous people that were featured on 60 Minutes who had gastric bypass. I thought that was the panacea. Then we began to see those patients come back. To some extent, obesity is a chronic disease. It goes into what I was saying that you really have to change your lifestyle with these procedures. What was interesting is the patients were telling us the same thing. I eat something. I feel lightheaded. The only way I relieve it at night is to eat more. It sounded like reactive hypoglycemia – the sugar going up and down.

We looked at different operations, and there was an operation called the duodenal switch. It was not used very much. It was considered very extreme. When we measured, we did not see the same glucose fluctuations. What we did is we simplified that operation and made it less drastic. It is called SADI-S. What is really interesting is when we put continuous glucose monitors, which are what diabetics wear, we do not see the ups and downs in glucose. I think that is very much more preferable for long-term control of weight and eating behavior. 

Host: 18:57
When should people start to be concerned about their weight? What questions should they be asking their doctors? What should they do to be proactive to make sure they are not going to become obese? 

Dr. Roslin: 19:05
Quality of food. Okay? 

  1. Quality of food: It goes back to what I was saying. Try to limit the chips, the packets, and the processed food.

  2. Active lifestyle: You cannot be healthy unless you are physically fit. We talked a lot about insulin and glucose. When you exercise, you actually do not need insulin to drive glucose into the cells. You have to be active.

  3. Sleep: This is really important for energy regulation.

  4. Mental health. If you are depressed and down, you are not burning. Again, everything is systemic. 

In terms of markers for obesity, I tend to think people judge whether you are metabolically healthy or not based on your glucose and hemoglobin A1C. I think that is a late sign. I think looking more at fasting insulin, this is another thing we would like to tackle through the medical school. It is by looking at this from an epidemiologic approach. Should we be looking at different biomarkers that would alert us earlier? 

Host: 20:10   
Yeah. When you say exercise, I think a lot of people’s initial reaction to exercise is, "Oh my God. I have to go join some expensive gym and I have to be doing all this work." Is walking good enough? 

Dr. Roslin: 20:20   
Anything is better. We were not made to be sedentary. Walking, running, swimming, cycling, dancing, or whatever you are going to do is an advantage. 

Host: 20:34   
That was such a fascinating conversation, Dr. Mitchell Roslin. Thank you so much for joining us here on 20-Minute Health Talk. 

Dr. Roslin: 20:40   
Thank you for having me. It really has been a pleasure. I hope to continue it sometime in the future. 

Host: 20:46   
Awesome. And for you the listener, thank you so much for tuning in.




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