Why Most People Regain Weight After Dieting
By Kenneth McLeod
Anyone who has tried to lose weight and keep it off knows how difficult the task can be. It seems like it should be simple: Just exercise to burn more calories and reduce your calorie intake. But many studies have shown that this simple strategy doesn't work very well for the vast majority of people.
A dramatic example of the challenges of maintaining weight loss comes from a recent National Institutes of Health study. The researchers followed 14 contestants who had participated in the "World's Biggest Loser" reality show. During the 30 weeks of the show, the contestants lost an average of more than 125 pounds per person. But in the six years after the show, all but one gained back most of their lost weight, despite continuing to diet and exercise.
Why is it so hard to lose weight and keep it off? Weight loss often leads to declines in our resting metabolic rate—how many calories we burn at rest, which makes it hard to keep the weight off. So why does weight loss make resting metabolism go down and is there a way to maintain a normal resting metabolic rate after weight loss? As someone who studies musculo-skeletal physiology, I will try to answer these questions.
Activating muscles deep in the leg that help keep blood and fluid moving through our bodies is essential to maintaining resting metabolic rate when we are sitting or standing quietly. The function of these muscles, called soleus muscles, is a major research focus for us in the Clinical Science and Engineering Research Center at Binghamton University. Commonly called "secondary hearts," these muscles pump blood back to our heart, allowing us to maintain our normal rate of metabolic activity during sedentary activities.
Resting Metabolism and Weight Maintenance
Resting metabolic rate (RMR) refers to all of the biochemical activity going on in your body when you are not physically active. It is this metabolic activity that keeps you alive and breathing, and very importantly, warm.
Quiet sitting at room temperature is the standard RMR reference point; this is referred to as one metabolic equivalent or MET. A slow walk is about two MET, bicycling four MET and jogging seven MET. While we need to move around a bit to complete the tasks of daily living, in modern life we tend not to move very much. Thus, for most people, 80 percent of the calories we expend each day are due to RMR.
When you lose weight, your RMR should fall a small amount, as you are losing some muscle tissue. But when most of the weight loss is fat, we would expect to see only a small drop in RMR, as fat is not metabolically very active. What is surprising is that relatively large drops in RMR are quite common among individuals who lose body fat through diet or exercise.
The "World's Biggest Loser" contestants, for example, experienced a drop in their resting metabolic rate of almost 30 percent even though 80 percent of their weight loss was due to fat loss. A simple calculation shows that making up for such a large drop in RMR would require almost two hours a day of brisk walking, seven days a week, on top of a person's normal daily activities. Most people cannot fit this activity level into their lifestyle.
There's no question that eating a balanced diet and regular exercise are good for you, but from a weight management perspective, increasing your resting metabolic rate may be the more effective strategy for losing weight and maintaining that lost weight.
The Connection Between RMR and Your Heart
Metabolic activity is dependent on oxygen delivery to the tissues of the body. This occurs through blood flow. As a result, cardiac output is a primary determinant of metabolic activity.
The adult body contains about four to five liters of blood, and all of this blood should circulate throughout the body every minute or so. However, the amount of blood the heart can pump out with each beat is dependent on how much blood is returned to the heart between beats.
If the "plumbing" of our body, our veins in particular, was made of rigid pipes, and the skin of our legs was tough like that of bird legs, cardiac outflow would always equal cardiac inflow, but this is not the case. The veins in our body are are quite flexible and can expand many times their resting size, and our soft skin also allows lower body volume expansion.
Cardiac output controls resting metabolic rate.Shutterstock
As a result, when we are sitting quietly, blood and interstitial fluid (the fluid which surrounds all the cells in our body) pools in the lower parts of the body. This pooling significantly reduces the amount of fluid returning to the heart and correspondingly, reduces how much fluid the heart can pump out during each contraction. This reduces cardiac output, which dictates a reduced RMR.
Our research has shown that for typical middle-aged women, cardiac output will drop about 20 percent when sitting quietly. For individuals who have recently lost weight, the fluid pooling situation can be greater because their skin is now much looser, providing much more space for fluids to pool. This is especially the case for people experiencing rapid weight loss, as their skin has not had time to contract.
Raising Metabolic Activity
For young, healthy individuals, this pooling of fluid when sitting is limited because specialized muscles in the calves of the legs—the soleus muscles—pump blood and interstitial fluid back up to heart. This is why soleus muscles are often referred to as our "secondary hearts." However, our modern, sedentary lifestyles mean that our secondary hearts tend to weaken, which permits excessive fluid pooling into the lower body. This situation is now commonly referred to as "sitting disease."
The soleus muscles keep blood from pooling in the legs.Henry Vandyke Carter / Wikimedia Commons
Moreover, excessive fluid pooling can create a vicious cycle. Fluid pooling reduces RMR and reduced RMR means less body heat generation, which results in a further drop in body temperature; people with low RMR often have persistently cold hands and feet. As metabolic activity is strongly dependent on tissue temperature, RMR will therefore fall even more. Just a 1 degree Fahrenheit drop in body temperature can produce a 7 percent drop in RMR.
One logical, though expensive, approach to reduce fluid pooling after weight loss would be to undergo cosmetic surgery to remove excess skin to eliminate the fluid pooling space created by the weight loss. Indeed, a recent study has confirmed that people who had body contouring surgery after losing large amounts of weight due to gastric banding surgery had better long-term control of their body mass index than people who did not have body contouring surgery.
What Can You Do?
A much more convenient approach to maintaining RMR during and after weight loss is to train up your secondary hearts, or soleus muscles. The soleus muscles are deep postural muscles and so require training of long duration and low intensity.
Tai chi, for instance, is an effective approach to accomplish this. However, we've observed that many people find the exercises onerous.
Over the last several years, investigators in the Clinical Science and Engineering Research Lab at Binghamton University have worked to develop a more practical approach for retraining the soleus muscles. We have created a device, which is now commercially available through a university spin-off company, that uses a specific mechanical vibration to activate receptors on the sole of the foot, which in turn makes the soleus muscles undergo a reflex contraction.
In a study of 54 women between the ages of 18 and 65 years, we found that 24 had secondary heart insufficiency leading to excessive fluid pooling in the legs, and for those women, soleus muscle stimulation led to a reversal of this fluid pooling. The ability to prevent or reverse fluid pooling, allowing individuals to maintain cardiac output, should, in theory, help these individuals maintain RMR while performing sedentary activities.
This premise has been confirmed, in part, by recent studies undertaken by our spin-off venture. These unpublished studies show that by reversing fluid pooling, cardiac output can be raised back to normal levels. Study results also indicate that by raising cardiac output back to normal resting levels, RMR returns to normal levels while individuals are sitting quietly. While these data are preliminary, a larger clinical trial is currently underway.
Kenneth McLeod is an entrepreneur in residence and director at the Clinical Science and Engineering Research Laboratory at Binghamton University, State University of New York. Reposted with permission from our media associate The Conversation.
Could mouthwash help stop the spread of the new coronavirus?
- How to Stop Touching Your Face to Minimize Spread of Coronavirus ... ›
- Vodka Won't Protect You From Coronavirus, and 4 Other Things to ... ›
EcoWatch Daily Newsletter
By Naomi Larsson
For centuries, the delicate silver dove has been a symbol of love and fidelity.
Biodiversity and Habitat Loss<p>Their near extinction is a symbol of the <a href="https://www.dw.com/en/global-biodiversity-outlook-targets-extinction-summit-new-york-pledge/a-54932895" target="_blank">biodiversity crisis</a> in the UK, largely driven by habitat destruction. Britain is now one of the countries with the most <a href="https://www.wwf.org.uk/future-of-UK-nature#:~:text=The%20UK%20is%20one%20of,than%20half%20are%20in%20decline" target="_blank">depleted nature</a> in the world according to the World Wildlife Fund. Half its plant and animal species are in decline and more than <a href="https://www.rspb.org.uk/about-the-rspb/about-us/media-centre/press-releases/let-nature-sing-wales/#:~:text=a%20natural%20tragedy.-,Over%2040%20million%20birds%20have%20vanished%20from%20UK%20skies%20in,unaware%20of%20the%20impending%20danger" target="_blank">40 million birds</a> have vanished in just half a century.</p><p>"[Turtle doves] are the canary in the [coal] mine because there are all these other species before it and after it," said Tree. "It's an umbrella for all the other species that are heading that way."</p><p>Turtle doves migrate south through Europe to sub-Saharan Africa between July and September, ending up in dry woodland and farmland areas of countries like Mali and Senegal for winter. </p><p>Droughts in West Africa and the Sahel region are believed to have contributed to the fall in turtle dove species recorded in northern Europe, with low rainfall reducing supplies of the seeds and insects the birds rely on for energy for the long journey home.</p>
Conservation and Farming<p><a href="https://www.operationturtledove.org/" target="_blank" rel="noopener noreferrer">Operation Turtle Dove,</a> a partnership project of charities including the Essex Wildlife trust, works with landowners and farmers to actively build turtle dove habitat.</p><p>Outten works with <a href="https://www.ebws.org.uk/birdsites/blue-house-farm-ewt-north-fambridge" target="_blank">Blue House Farm</a>, a 660-acre nature reserve in the UK county of Essex, where they have replicated weedy fallow plots. </p><p>"We work on it every year to make sure it's in the condition it needs to be with plants such as clovers and black medic," Outten said. "These plants are native to the landscape and produce the seed the birds feed on." </p><p>The birds eat a wide range of seeds from various plants that would have been abundant 50 or 100 years ago, added Guy Anderson, program manager for species recovery with The Royal Society for the Protection of Birds (RSPB). </p><p>"But it's simply true that with the gradual process of <a href="https://www.dw.com/en/farming-without-pesticides-how-can-we-make-agriculture-greener/a-52216796" target="_blank" rel="noopener noreferrer">intensifying our agricultural production</a>, the availability of those seeds has dropped and dropped," said Anderson.</p><p>Part of the project includes supplementary feeding — providing sources of food in the form of seed or grain. Under the Countryside Stewardship Scheme in England, farmers can receive financial support to create a turtle dove habitat. </p><p>Though they haven't recorded an increase in doves across the sites in the four years of working on the project, Outten said they are seeing improvements in how landowners and farmers manage habitat for the birds. </p>
A Turtle Dove Haven<p>The 3,500-acre Knepp Estate in West Sussex is another project taking a different approach and one of the few places where turtle dove numbers are increasing.</p><p>Isabella Tree and her husband Charlie Burrell converted their intensively farmed land into a rewilding project almost 20 years ago. They have let the land return to nature.</p><p>Just one year after they'd finished <a href="https://www.dw.com/en/uks-most-talented-architects-are-not-human/a-35952128" target="_blank">rewilding</a> the southern part of their property, they heard turtle doves for the first time. It's now a breeding hotspot for the birds with an estimated 19 pairs. Knepp is also home to <a href="https://www.rewildingbritain.org.uk/rewilding/rewilding-projects/knepp-estate" target="_blank" rel="noopener noreferrer">2% of the UK's population</a> of nightingales. </p><p>Tree is critical of supplementary feeding schemes that, in her view, are short term. She questions the chances of turtle doves getting to feed on scattered seeds before other mammals eat them first.</p>
- 41% of UK Species Have Declined Since 1970, Major Report Finds ... ›
- One in Eight Bird Species Threatened With Extinction, Study Finds ... ›
- Pesticides to Blame for UK's Declining Turtle Dove Population ... ›
We pet owners know how much you love your pooch. It's your best friend. It gives you pure happiness and comfort when you're together. But there are times that dogs can be very challenging, especially if they are suffering from a certain ailment. As a dog owner, all you want to do is ease whatever pain or discomfort your best friend is feeling.
Life-sized, ultra-realistic robotic dolphins could help end animal captivity by replacing living creatures in aquariums and theme parks.
- Keeping Large Mammals Captive Damages Their Brains - EcoWatch ›
- Scientists Combine AI With Biology to Create Xenobots, the World's ... ›
- Singapore Uses 'Scary' Robot Dog to Enforce Social Distancing ... ›
By Jessica Corbett
Green groups applauded Sen. Jeff Merkley on Wednesday for introducing a pioneering pair of bills that aim to "protect the long-term health and well-being of the American people and their economy from the catastrophic effects of climate chaos" by preventing banks and international financial institutions from financing fossil fuels.