Losing Weight Can Make You Gain Weight- Understanding The Paradox
One of the most frustrating aspects of losing weight is the inherent difficulty in sustaining weight loss over an extended period of time. A difficulty that is perhaps most pronounced among those who are severely overweight and use a combination of calorie restricted diets and aerobic exercise. Regardless of whether the goal is to lose twenty pounds or fifty pounds, the experience for most people is an early (and welcome) loss of weight that slowly and inexplicably grinds to a halt over time. In many cases, weight loss begins to reverse itself with a gradual increase in weight over time. Weight gain that continues even in the face of increased efforts to restrict calories and increase duration and volume of exercise in the hopes of stopping the upward movement of the numbers on the scale. Frustrated and discouraged, most will lay the blame on everything from a genetically slow metabolism to some mystical sensitivity to carbohydrates- when the reality is far more complex. In fact, weight loss is indeed one of the most complex issues that most of us will face in our lives, as it is affected not only by physical factors, but behavioral and psychosocial ones as well. Our media often dumbs it down as a way to use weight loss information as a form of entertainment, or as a vehicle to sell products, and such an approach does little for the individual wishing to understand its complexities. For it is only through an understanding of those complexities that anyone can hope to master the challenges that losing weight presents. In this article we will explore the physical mechanics of the yo-yo weight loss/weight gain effect and show why losing a large amount of weight actually predisposes you to regaining it easily. Most especially if the weight loss occurs within a short space of time.
An understanding of why most people regain weight first requires some familiarity with how our bodies expend energy and there are three main factors to consider. The first and by far the largest and most important component is our resting metabolic rate or RMR, which accounts for 65- 75% of total daily energy expenditure in sedentary adults.[1,5,9] Like the closely related basal metabolic rate, measured while completely at rest, RMR is measured under slightly less controlled conditions, but gives a good estimate of daily energy expenditure nonetheless. Resting metabolic rate depends mainly upon quantity of lean muscle mass, and to a lesser degree, thyroid hormones and protein behavior. The second component of energy expenditure is known as work induced increase above resting metabolic rate (which we will refer to from hereon as WIT to make matters simple) and it refers to the amount of energy used in physical activity. Obviously this figure varies widely as it depends on how physically active an individual may or may not be. For example, an athlete or someone engaged in large amounts of manual labor would logically have a higher WIT than a sedentary individual. The final component of energy expenditure is diet induced thermogenesis (DIT) which refers to the energy used by our bodies to digest foods. Proteins, for example are known to have a significant thermic effect as they require more calories for digestion than carbohydrates or fats due to its molecular structure. However, digestion of all foods incur an increase in energy expenditure, thus diet related thermogenesis accounts for about 10% of our daily expenditure. Among obese individuals this percentage can be lower possibly due to increased insulin resistance which has some effect on calories used during digestion.[3,4]
Losing Weight Can Make You Gain Weight- The Bigger You Are the More Calories You Burn
Contrary to the myth of slow metabolisms among people who are overweight, the absolute energy expenditures of individuals who are obese are generally higher than that of someone of a lower bodyweight. Two factors account for this discrepancy:
- Individuals who are obese tend to have higher fat free mass than those who are not.[5,6]
- Larger bodies require more energy to move and thus expend more calories in physical movement.
This makes perfect sense as a larger body requires more energy to move than a smaller one. As a prime example- men on average burn more calories than women because they generally have higher body weights and more lean muscle mass. This relationship between weight and energy expenditure is one of the reasons endurance athletes try to shed any excess pounds so as to use less energy during events. The differences are notable as a typical 190lb man burns 1,380 kilocalories per hour running at a pretty fast pace of 11 miles per hour but a 130lb man uses 40% less running at the same pace. That’s why you’ll seldom see someone on the larger side winning major marathons or distance type events, as natural selection favors those with smaller, more energy efficient bodies in the winners’ circle. With regards to weight loss, it then makes perfect sense that the more weight you lose, the fewer calories you’ll burn, while exercising.[8,9,10]
That’s not the only reason weight loss brings about a decrease in energy expenditure as there usually also an increase in mechanical efficiency. When someone loses a significant amount of weight, their efficiency in the performance of physical exercise will increase. Such adaptations mean fewer calories will be burned while exercising. These are some of the factors that account for weight loss never being perfectly linear, but instead tends to slow down and eventually reverse over time. A reversal and slowing that was at one time attributed to the set point theory.
Losing Weight Can Make You Gain Weight-Set Point Theory Explained
Set point theory neatly placed the blame on the proclivity of most obese individuals to return to their previous weight with the idea that our body has a homeostatic feedback system for keeping our fat stores constant. A system that would do everything possible to return you to previous body fat levels if you lost weight by creating adaptive changes in resting metabolic rate and thyroid hormones. Set point theory set the stage for weight loss as a bleak and somewhat Sisyphean task for those trying to slim down. However, although it was once regarded as scientifically plausible, further research has disproved it over the years as studies have failed to find hormonal or metabolic compensations that can neatly explain the tendency for most people to regain weight.
Losing Weight Can Make You Gain Weight- Decreases In Resting Metabolic Rate
What has been observed is an often dramatic slowing of resting metabolic rate (RMR) among those who lose significant amounts of weight. Due largely to the decrease in lean muscle mass that accompanies standard weight loss protocols of caloric restriction and or aerobic exercise. This significant decrease in metabolism due to reductions in muscle mass, when combined with other decreases due to lower body weights accounts for the tendency for most people who lose weight to regain it.[8,12,13,14,15,16,17,18,19,20]
We have established that for most individuals weight loss is usually achieved as a result of a negative energy balance diet. You eat less calories than your body needs while including some aerobic exercise in the hopes of burning off a bit more and you will lose weight. But as most can attest, only for a limited amount of time. Reduction in resting metabolic rate and work induced increases above metabolic rate (WIT) after losing weight means that eventually the low calorie diet and exercise plan that helped you lose weight won’t work indefinitely and may actually make you gain weight over time.
The Biggest Loser- A Study In Weight Regain Predisposing Factors
This disturbing fact was highlighted recently in a study of competitors undergoing massive weight loss during a popular weight loss television reality show called the Biggest Loser. Seven males and three females- all significantly overweight were trained under supervised conditions for an average of two hours a day, six days a week for thirty weeks doing a combination of aerobics and circuit training. Dietary intake was advised to be at least 70% of baseline energy requirements and every seven days a participant was voted off the ranch and returned home to continue the program unsupervised for the duration of the thirty week period. All participants were measured at the conclusion coincident with a live television broadcast.
After thirty weeks participants lost between 127lbs and 52 lbs. An extreme reduction to say the least as participants lost as much as 40% of their initial body weight. Such weight loss came at a price- as fat free muscle mass accounted for approximately 17% of the total weight lost. Concordant with a drop in muscle mass, resting metabolic rates plummeted from baseline figures by about 350 kcal per day after the first 6 weeks and went down to a low of about 790 kcal per day. Putting this into perspective, a reduction of almost 800 kcal would mean contestants would have to eat at least two whole meals less than what they started with to maintain their weight loss while continuing to follow an unrealistic training program for two hours six days a week for the rest of their lives. Possibly even less food would be required over time as metabolism demands decrease with age, making sustainable weight loss a challenge to say the least.
A Solution to Weight Regain Through Increasing Muscle Mass & High Intensity Training
Less extreme and closer to standard weight loss protocols don’t fare much better for weight loss as well, as those using hypocalorie diets alone average a decrease of 25% of fat free muscle mass. While the authors of the Biggest Loser study hold a muscle mass loss of 17% as relatively small amount, it’s clear for anyone to see that such losses are significant enough to make weight regain becomes almost inevitable without continued extreme interventions. Other weight loss interventions such as bariatric surgery also bring about undesirable reductions in fat free muscle mass that result in slower overall metabolism and a high likelihood of weight regain over time.[12,13,14] Such findings might lead us to conclude that significant weight loss in the long term is unrealistic, but this is far from being the case as conventional approaches ignore the application of high intensity resistance training focused on muscle building as a viable protocol for long term weight management.
The most important part of any sustainable weight loss program is not simply burring off calories through cardiovascular exercise and lower calories, but rather the idea of focusing instead on INCREASING muscle mass. Increased muscle mass means higher resting metabolic rates, which allows for calorie intakes to remain higher and within more natural and practical limits for the average member of the population. (See my article on the Evolutionary Argument For Eating More To Lose Weight) Several reputable studies confirm the role of resistance training in preserving muscle mass during diet induced weight loss and a concurrent increase in fat mass losses as a result, [24,25,26,27] and it is an approach that I have used in my own practice for the past twenty-one years. If resting metabolic rates account for 75% of daily energy expenditure and is determined by fat free muscle mass then trying to lose weight by employing practices that decrease muscle mass is inevitably counterproductive.
On the other hand, increases in fat free muscle mass from weight training lead to higher resting metabolic rates.[9,27] Which, when combined with the added calories burned during resistance training and from excess post exercise oxygen consumption, can gradually and permanently decrease body fat levels when used in conjunction with muscle promoting high protein diets that are not overly hypocaloric.(22,23,28,30)
Aerobic Exercise Vs Resistance Exercise For Long Term Weight Loss
Skepticism has always existed regarding the use of muscle building exercise as a protocol for weight loss, as aerobic exercise is typically associated with losing body fat, even though numerous studies find high intensity weight training as being more efficient than conventional aerobic exercise for reductions in fat mass.[22,23] Aerobic exercise can indeed reduce fat mass, but has little effect if any on the preservation of fat free mass. [29,30,31] Not only does this increase the possibility of weight regain, but from a cosmetic point of view, diet induced weight loss using such forms of exercise would result in a smaller, but still flabby version of what you started out with if resistance exercise is not included in your regime. There is a slight increase in calorie expenditure for 20-48 hours after aerobic exercise, but only if such exercise is done with sufficient intensity and relatively long duration.[32,33,34,35] Except for this small window, there is, however no increase in resting metabolic rates regardless of how much aerobics you do. On the other hand, increases in fat free muscle mass permanently increase resting metabolic rates- and the so called after burn effect of high intensity training from excess post exercise oxygen consumption is also greater than that of aerobic exercise.[22,23]
The other factor that favors high intensity resistance training for long term weight loss without weight regain is the use of a high protein diet designed to increase muscle mass. Studies have shown that a high protein intake of 18% or more of total energy intakes limits weight regain in those who have lost weight. Diet induced thermogenesis accounts for about 10% of energy expenditure and high protein foods not only have a high thermogenic and muscle sparing effect, [9,28] but also promote higher satiety levels after consumption which can limit excessive calorie intake. [36,37,38,39]
Practical & Sustainable Solutions Through Resistance Exercise & High Protein Diet
In my own practice over the course of twenty one years I have records of thirty one significantly overweight individuals who lost over 50lbs using only a combination of high intensity weight training and a high protein diet. Calorie intake was not at all restrictive as emphasis is on long term adherence and was calculated more in line with the focus on muscle growth and preservation as opposed to simply inducing negative energy balance. Notably among those thirty-one trainees, eight of them lost over 100 lbs and such weight loss is very much on par with the some of the numbers cited in the Biggest Loser study. However, the process was centered on lifestyle change, took far longer (an average of 12-14 months) and did not involve more than thirty minutes of high intensity training per week. Unconventional, to say the least, but an effective program built on the science of maximizing resting metabolic rates, diet induced thermogenesis and absolute energy expenditure in a practical and sustainable manner. Most importantly increased muscle mass over time limited weight regain, as only 5 out of 31 trainees regaining more than 70% of the weight lost after a year- a success rate of 84% which is significant when compared to the failure rates of 35-80% reported in most studies. A sample size that is small, but one that calls for more research in the use of resistance training as a weight loss tool.
Reduction in body fat through high intensity weight training does not yield the quick decreases on the scale that would be seen from high volume aerobic exercise and low calorie diets- which in itself is a good thing as you don’t lose muscle mass in the process. However it does provide a long term solution for those needing to lose weight with the added benefits of increased strength and improved self esteem thanks to increased lean muscle mass. Muscle mass that is key to the development of the lean, toned and tight body that is without question the Holy Grail of our time. A look that is unattainable from high levels of aerobics and or low calorie intakes, as such activities have little effect on the increased development of skeletal muscle and from what we know can predispose you to regaining the weight you worked so hard to lose.
Kevin Richardson is an award winning health and fitness writer, natural bodybuilding champion, creator of Naturally Intense High Intensity Training and one of the most sought after personal trainers in New York City. Read more about the science behind his high intensity training programs at his official website at www.naturallyintense.net
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