Nearly half of all U.S. adults have tried to lose weight in the last 12 months. Obesity is often described as an epidemic. A health care crisis even. In this episode, endocrinologist Amy Rothberg, M.D. joins us to talk about weight loss and the most commonly searched questions about weight management.
- What foods help you lose weight the fastest?
- Is there a danger to losing weight too fast?
- Does intermittent fasting work?
Fad diets and promises of quick weight loss get a lot of attention in the media, but Dr. Rothberg helps us get into the science and we really know about weight loss.
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Transcript
Dr. Preeti Malani:
Weight loss is always a topic of intense interest and that's no surprise. Nearly half of all US adults have tried to lose weight in the last 12 months. Obesity is often described as epidemic or even a healthcare crisis. Today, we're going to talk about weight loss and the most commonly asked questions about weight management, everything from intermittent fasting to apple cider vinegar. Fortunately, we'll be getting answers from an expert on the topic, Michigan Medicines, Dr. Amy Rothberg, an endocrinologist and Director of the University of Michigan Health Weight Management Program. Fad diets and promises of quick weight loss are often at the front of these conversations, but we're going to get into the science and talk about what we really know about weight loss. Let's get started.
I'm Dr. Preeti Malani. Thank you for joining us on the Michigan Answers Podcast.
Dr. Rothberg, thanks for joining us today.
Dr. Amy Rothberg:
My pleasure to be here.
Dr. Preeti Malani:
Okay. You know the premise. We take a topic, in this case a topic that you know very well, and I'll ask you some of the most searched questions for the topic on Google.
Dr. Amy Rothberg:
Is there a prize for knowing the right answers?
Dr. Preeti Malani:
Well, kind of. Your prize is knowing that you helped our listeners understand this complicated topic, and this is going to be a lot of fun, and I might add a couple of questions on my own.
Dr. Amy Rothberg:
I hope so.
Dr. Preeti Malani:
You ready for question one?
Dr. Amy Rothberg:
I am ready.
Dr. Preeti Malani:
Here we go.
So what foods are good for weight loss? In particular, we're seeing a lot of questions about whether there are certain foods like apple cider vinegar, oatmeal. Are these magical foods for weight loss.
Dr. Amy Rothberg:
Well, let me start off by saying, there are plenty of good foods such as vegetables, whole grains, minimally processed or no processed foods, and maybe not so good foods. What comes to mind with respect to the latter is sugar sweetened beverages. But when it comes to weight loss, it distills down to the concept of caloric density. So what do I mean by that? Caloric density is a measure of the calorie content of food relative to its weight or volume. So foods like broccoli are low in caloric density. You can eat a whole lot of broccoli for very few calories compared to a donut, which although may taste good in the moment, is not filling and energy dense; high in fat, high in sugar, fried, and very high in calories relative to its volume.
So there is no one magic food, and we really need to be skeptical of any claim that there is a single or a magical potion for weight loss. What I find sobering is that Americans spend close to $40 billion per year on weight loss products, the majority of which do not contribute to any meaningful, sustainable, weight loss. And while there are certainly proponents of consuming apple cider vinegar for its purported health benefits, and that it may curb appetite before meals or even burn fat, there is just no scientific evidence that it does. In fact, it may cause harm. Given its acidity it can strip the enamel from our teeth, can burn the throat, and even cause gastrointestinal upset.
So let's just talk about oatmeal since you mentioned that. Oats and oatmeal do have many healthful properties. They're a good source of vitamins, minerals, antioxidants, and they are very high in fiber. And so given that fiber content, they can lead to making one feel fuller and so we avoid consuming other foods.
Dr. Preeti Malani:
So it's really about moderation, what you put in, and trying to be thoughtful about what you are eating.
Dr. Amy Rothberg:
Absolutely. I could not have said it better.
Dr. Preeti Malani:
Great. So next question. Why does weight loss lower blood pressure? What's the connection there?
Dr. Amy Rothberg:
So body weight and obesity, specifically visceral or fat around the organs, are known to be independent risk factors for hypertension. And by reducing our calories, which consequently leads to weight loss, we can also reduce our blood pressure. And there have been both randomized and non-randomized studies of calorie restriction showing that early on even, with caloric restriction, even before there's a lot of weight loss, that calorie restriction alone can lower systolic, diastolic, so the top and bottom numbers, and the mean arterial pressure in both men and women. And the greatest gains are seen in those with really higher degrees of blood pressure when compared to just eating the standard Western diet.
And although we really don't understand all the mechanisms involved, several studies have suggested that improvement in blood pressure is related to actually improvement in insulin sensitivity, which I'll talk about, as well as increased nitric oxide production, which improves endothelial function. In addition, calorie restriction is known to induce expression of a really important nutrient sensor called SIRT1, which is linked to a number of beneficial metabolic benefits, and also probably results in improved longevity, so we live healthier and longer.
Dr. Preeti Malani:
So what I take away from that is a lot of focus with weight loss tends to be on aesthetics and how you look, but even small amounts of weight loss can start to make your body healthier.
Dr. Amy Rothberg:
True. We know that losing weight can reverse a lot of health conditions. We just talked about one, which is blood pressure, diabetes, which is sort of my bailiwick, which I focus on in my career. But we and others have actually proven that diabetes, especially for those who are newly diagnosed or who have had diabetes for only a few years can have complete remission of their diabetes by reducing calories, getting regular physical activity, and maintaining those lifestyle changes. Both insulin sensitivity and insulin secretion improve and the beta cells, so those insulin producing cells, recover.
Dr. Preeti Malani:
And I'm sure you've heard this one before. How can I lose weight quickly?
Dr. Amy Rothberg:
Well, the truth is that one can lose weight quickly, but it requires significant calorie restriction. We, in our program, do put people on an aggressive caloric restriction. There are a couple of concerns. While we can dramatically reduce calories, often alongside that calorie deficit are deficits in vitamins, minerals, and macro nutrients. So we can reduce calories to as few as 800 calories per day. But this has to be done with specialized formula diets and under medical supervision. If not, those on that low of calories, which we term a very low calorie diet, can be susceptible to electrolyte changes, dehydration, and kidney stones if not consuming enough water, low blood pressure, low blood sugar, if on hypoglycemic medications for the treatment of diabetes and gout. But those living at higher weights, for example, a woman, for example, who's 50 years old, maybe five foot four inches in height and 250 pounds, and who may want to get back to her weight when she was 30 years old and before having her children, may find it more motivating to engage in lifestyle change long-term if upfront she's able to lose a lot of weight in a relatively shorter period of time.
Indeed, there is a lot of data, including data from our group, that the biggest predictor of both short and long-term weight loss success is how much is lost in the first two weeks of a prescribed dietary intervention.
Dr. Preeti Malani:
So you just answered the question on how to lose weight quickly. There are also a lot of online searches about the consequence of sudden drastic weight loss. And you just talked about some of those. What are the trade-offs to losing weight too fast?
Dr. Amy Rothberg:
I'm glad you asked that question and this follows what I said a minute ago. There is no scientific validity to lose weight more slowly as one is less susceptible to weight regain versus lose weight quickly. If that were true, bariatric surgery, which is one of the most effective interventions for weight loss, would be considered unsafe and obsolete. The issue is that once one has lost weight, lifestyle modifications, again, true after bariatric surgery, as the surgery is not a permanent fix, need to persist to prevent weight regain. In other words, except for the caveats that I mentioned before related to aggressive calorie restriction, it doesn't matter how fast you got there, it matters what you do once you've lost the weight. And this is true for any weight loss intervention, surgery or lifestyle.
Dr. Preeti Malani:
That's a great segue to the next question, which is what do you tell people who ask how do they keep weight off after they worked so hard to lose it?
Dr. Amy Rothberg:
I'm going to take some time to answer this question, so I beg your indulgence. It's very hard to lose weight. Unless you've never tried, you don't know how hard it is. It doesn't help that we live in an environment that is entirely counterproductive to achieving and maintaining weight loss. We have access to an abundance of ultra-processed cheap and very seductive food. And everywhere we look there are messages about food. Most of our social gatherings are around food. But as I mentioned before, and this is where diet fatigue often sets in, we have to continue to employ all of the behavioral skills and maintain a much lower calorie intake to keep our weight off. And for those who have done the difficult work of losing weight, they get discouraged when despite continuing to stick to low calories, their weight loss slows down or even plateaus. And this can lead to poor motivation to keep going.
Let me just talk a little bit about the biology. There are a number of counterregulatory processes that are set in motion when we are weight reduced, which defend our higher weight. Our hormones that let us know we're full are actually dampened down. One hunger hormone called ghrelin actually increases. And our resting metabolic rate, which is the largest contributor to energy expenditure also goes down and we get more efficient with the calories we do take in. That's the bad news. So it's not that the individual isn't working hard. It's the biology in our current environment, those gene, gene, gene, environmental actions that are working against us.
But as time goes on, those counterregulatory processes exert less of a force. But it's important to understand that for the weight loss to stick, again, we have to be vigilant about keeping to fewer calories, getting regular physical activity, and adhering to all those behavioral modifications that we employed when we were losing weight. Along with that, I'm just going to say how vital it is to have a support system in place to help that individual during that very vulnerable period.
Dr. Preeti Malani:
So basically this is hard work, and it doesn't end with the weight loss.
Dr. Amy Rothberg:
It is hard work, and the hard work really begins after weight loss, but as we indoctrinate those behaviors, it does get easier with time.
Dr. Preeti Malani:
Okay. So I'm going to add a question because I'm wondering about this. With obesity being such a major health concern there's obviously a lot of research going on in this area. What emerging science on weight loss or weight management are you most excited about?
Dr. Amy Rothberg:
10 years ago, we had only two FDA approved medications for the treatment of obesity. Now we have a number of them approved, not just for weight loss, but for long-term weight control. And we're seeing more medications on the horizon. These drugs target some of the major receptors in our brain, which is the master regulator for weight control, which enhance our sense of early fullness and reduce cravings and hunger. One of the most recent drugs to emerge on the market has a percent weight reduction that approximates weight loss after bariatric surgery. I think these medications will transform how we manage weight.
There's also a lot of excitement regarding the benefits of something that falls under intermittent fasting called time restricted feeding or TRF. Most of the data is from rodent studies, although in the past few years there have been some small well controlled human studies. TRF is the concept of censoring consumption between a much narrower window so that naturally or organically the period of time during which we fast is extended. We especially in the US eat over a 12 hour day. So if we reduce that period to eight hours, for example, we can improve a host of metabolic and pro-inflammatory processes. This is really timely given COVID as we talk about all the sort of inflammatory cascade. But translation, when we fast, we clean up a lot of damaged organelles and cellular components in our body, rejuvenate the cell cycle and molecular pathways, and then again, we live longer and healthier.
What we don't know is what the optimal time window of the eating versus fasting should be. It also appears that we need to align that period with our circadian clock. So we should be eating our largest meals more in the early and mid part of the day and not eating, or certainly eating a lot less, in the evening. I think we know that intuitively. The Greeks practiced this, so it's not new, but we have more of an understanding of the metabolic and health benefits.
Dr. Preeti Malani:
Well, all of that gets at the whole environmental piece that you talked about and just having a support system that can help encourage us not to eat a big meal right before bed, for example.
Dr. Amy Rothberg:
Absolutely.
Dr. Preeti Malani:
Okay, Dr. Rothberg, I said there wasn't a prize, but I would say you've earned one. So thank you for sharing your time with us today and all this great information.
Dr. Amy Rothberg:
You're welcome. It's been my pleasure.
Dr. Preeti Malani:
Thank you for listening to this week's episode of Michigan Answers. If you enjoyed today's episode, please subscribe wherever you get your podcasts. This season we'll be unpacking some of the most searched for health topics on the internet. And if you're interested in learning more about how Michigan Medicine is improving lives and advancing health, please visit us at michigananswers.com. See you next week.
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