How the weight can be lost and then maintained at a constant level, Exercise alone is not the answer
Updated: Nov 19, 2020
I have seen, among my friends and other acquaintances, about the myths of weight loss, the role of exercise, and the sagas of ill effects of skipping meals. Whenever I have time and an appropriate place, I always start the conversation and try to put logic into it. But there is not always enough time to go through the minor details and to make the person understand the full mechanism of loss of weight.
I have already written an article, months before, about the way a person should start weight loss, but I will take this opportunity to put a little more detail into it. I want to encourage interested people to start the process of weight loss. Try to read this article to the end, and if possible, comment and take part in the conversation, so that we can have ideas of different people about the weight loss.
Benefits of considering weight loss
Let me put this into perspective:
Healthy status and better cardiovascular tolerance with a decrease chance of heart attacks, strokes, and hypertension (One study published in Cell Metabolism journal this month concluded that cutting calorie intake by 15 percent over two years can slow aging and protect against diseases such as cancer, diabetes, and Alzheimer’s).
Fewer intakes will lead to a slower metabolism which puts less burden on the machinery of the body (A slowed metabolism is linked to longer life in hundreds of animal species, said Leanne Redman, Ph.D., associate professor of clinical sciences at Pennington Biomedical Research Center in Louisiana and a co-author of the study).
Less chance of getting osteoarthritis due to increase weight (Being overweight is a clear risk factor for developing OA. Population-based studies have consistently shown a link between overweight or obesity and knee OA).
Better personality, better attitude towards life, increase in self-esteem, and better way to see the world (eating Less Improves Mood, Sleep, and Sex Drive in Healthy People, Study Finds).
Change of the way people at large perceive you.
A decrease in consumption, a better understanding of saving food, and consuming less than what is required. You can have a chance to be a participant in improving climate change and saving the planet earth, without you even being a social worker or an enthusiast.
Decreasing the burden on your pocket by decreasing the consumption of food. Getting a chance of improving your economic condition within the same resources.
Many more benefits can be listed, as the list is never exhausting, but I will leave it to the readers to add a few more in the comments.
Understanding the mechanism
Before you opt to start losing weight, a better understanding of the nutrients, and the way they work and metabolized in the body is important.
Our normal diet is mostly consisting of carbohydrates, proteins, fats, fiber, vitamins, and minerals. Proteins, carbohydrates, some vitamins, and most minerals are using a similar mechanism for absorption through the intestinal mucosa, after digestion. Fats will use a different mechanism for absorption along with a different way of travel within the blood. Fats, after absorption, are not carried to the liver, contrary to the other nutrients, which will always be taken to the liver first.
The whole digestion and absorption process requires a lot of energy. Our gastrointestinal (GI) tract is very efficient and will absorb nearly all the nutrients presented to it in normal situations.
Digestion and absorption of nutrients
The carbohydrates we take in our diet will ultimately be converted to very simple sugars during digestion, and mostly the end-product will be glucose, as in all of the staples (wheat, rice, corn), glucose is abundant. The pancreas remains a very important organ producing all of the most important enzymes required to breakdown all of the carbohydrates into simpler sugars, and thence broken down to the simplest sugars by intestinal lining enzymes into glucose (mostly), except for cellulose (which is a plant sugar, for which there is no enzyme in our body, hence it cannot be digested and will be part of undigested fecal material). Once glucose is released within the intestinal lumen, it will be actively absorbed through the intestinal cells. By active absorption, it is meant that it is an energy-dependent process and ferrying each molecule of glucose into the intestinal cells, requires energy. Once inside the cells, they will just diffuse out (without the use of energy, along the concentration gradient) of the cell into the blood, using specialized channels. When inside the blood, they travel towards the liver.
A very similar mechanism is involved in the absorption of water-soluble vitamins, and minerals, one exception being the sodium, which helps glucose, AAs and other carbohydrates to get absorbed into the blood. Without sodium, these nutrients cannot be absorbed in any condition (topic for yet another post).
Fats digestion and absorption is a different story. Fats and fat-soluble vitamins (Vit A, D, E, & K) will be using this mechanism for digestion and absorption. A very strong enzyme for the digestion of all fats is present in the pancreatic juice. This enzyme can work in an aqueous environment, i.e. it is water-soluble. To help this enzyme to work on fats or fat-soluble molecules, the liver produces a juice called bile. Bile has got no enzymes, it just emulsifies the fat and let it travel within an aqueous environment, which gives a chance to ever strong pancreatic fat destroying enzyme to work.
Emulsification can be best understood by comparing soap or dishwasher, which wipes all of the fatty material off of the utensils that water alone can’t. Once digested, fats enter the intestinal cells by simple diffusion, i.e. without using energy. Some manufacturing occurs within the cells and thence it is moved out of the cells. This moving out of intestinal cells towards the blood side uses energy. There is yet another difference here. Fats are larger molecules, they, therefore, cannot enter blood capillaries, so they will be taken up by lymphatics (which are another set of capillaries different from blood capillaries). Fats are then taken directly to the heart, bypassing the liver, and will be sent to general circulation throughout the body.
Metabolism of the nutrients
The liver is the primary organ to store excess glucose (remember the origin of this glucose, i.e. food). The ultimate storage form of glucose in all animals is glycogen. Liver and skeletal muscle cells can convert all excess glucose to glycogen, the liver being the most efficient. One difference between liver and skeletal muscle glycogen is that liver glycogen (stored glucose) can be released back into general circulation in the form of glucose when the need arises, but skeletal muscle cells can only use for themselves.
An increased amount of glucose coming from the GI tract soon after eating will stimulate the pancreas to release Insulin (pancreas,
in addition to producing digestive enzymes, can also produce hormones). The higher the surge of glucose, the more amount of insulin will be released. Longer and higher surges of glucose will lead to a higher and longer release of insulin from the pancreas. Here one important thing to remember is that there are just 1 million cells in Pancreas, which is the only organ, producing this hormone. Continuous burden of longer and higher stimulus may burn these cells out.
We will come back to insulin, but before, a complete understanding of the metabolism of glucose needs special emphasis.
The liver can store a huge amount of glycogen, nearly 5% of its total mass. When glucose supply is abundant and no more can be stored within the liver, the metabolic mechanism will change. Now the abundant glucose will be converted to free fatty acids (FFAs). Some FFAs can be stored within the liver, but most of them will be released in the blood to be carried to the adipose (fatty) tissues, the usual site of storage of fats. Adipose tissues can be found in buttocks, thighs, female breasts, under the skin, and sometimes in unusual places as well, e.g. in the abdominal wall, around the viscera, etc.
These FFAs when arriving at the adipose cells will be incorporated with glycerol. All adipose cells can convert excess glucose, in the presence of insulin, to another fat, called glycerol. When FFAs and glycerol combine, the ultimate storage form of fats is synthesized, called triglycerides. If the supply of FFAs and glycerol is abundant, more and more triglycerides can be made and stored. Do not forget the source of both these fats (FFAs and glycerol), i.e. glucose and not fats.
The AAs, after being taken to the liver, are then released into the blood for use by all the cells to manufacture proteins. AAs are also a stimulant for the release of insulin from the pancreas. More the number of AAs and the longer the rush, the more and for the increased duration, insulin will be released. Even, if you haven't taken much carbohydrates, but your intake of protein (meat) is very high, still there will be a same surge of insulin!
As fats are not taken to the liver, they travel in the blood and can enter other cells as well as adipose tissues. Fats are an important part of the structure and function of all the cells. Abundant fats are stored within the usual or unusual areas of our body.
Nutrients breakdown for energy
The body will always give preference to glucose for the use of energy. Central nervous system cells, i.e. neurons, can utilize only glucose for their energy use. They can also use ketone bodies, if the need may arise, but they will always prefer glucose. All other cells, especially skeletal muscle cells, can effectively and efficiently breakdown all the nutrients for energy, dependent upon the availability of each of them. Preference will always be given to glucose though. When the supply of glucose is abundant, all cells will use it. When the supply declines, skeletal muscle cells will breakdown stored glycogen to glucose. If both of these sources are exhausted, fats are broken down and are directly used for energy production. The liver can convert available fats to make new glucose by a process called gluconeogenesis (gluco = glucose, neo = new, genesis = to make). In certain circumstances, for example, extreme starvation, and under the effect of certain hormones, proteins are broken down and either used directly for energy or, in the liver, can be converted to glucose and released in the blood.
Insulin is the only hormone known to decrease blood glucose level, no other hormone exists doing the same job. But it is not merely a hypoglycemic (hypo = lower, glyc = glucose, cemic = in the blood) hormone, it has great jaw-dropping and awesome physiological functions. Some of its functions are yet to be known. It is a protein hormone (that is why it cannot be given as oral form) and once released will have a half-life of only 6 minutes in the blood. After combining with its cell surface receptor,
it exerts its effects through other intercellular chemicals. Some of its effects are immediate (e.g. lowering blood glucose level), occurring within minutes and disappear once its level in the blood decreases. Other effects start within hours and will continue for days. Some of its effects take days to start and continue for even weeks. Not all of the functions and effects of insulin are understood, despite monumental research efforts. In short, we can say that it is a bodybuilding hormone. Its effects can be seen working on the cells long after it has been disappeared from the blood.
The lowering of blood glucose effect is because it puts specialized channels on all cells of the body, except the neurons, through which glucose can pass into the cells. Without these channels, glucose will be unable to enter the cell. In the presence of insulin, blood glucose is ferried across all cell membranes (exception is neurons, because neurons don’t need insulin to get glucose) into the cells and used for energy. If abundant, skeletal muscles can store it in the form of glycogen and adipose cells convert it into fats (as described above). When insulin is not there, as it happens between meals, no cells can take in glucose (except neurons). They will be forced to utilize first the stored glucose and then the fats.
After we have understood the normal mechanism of energy provision and breakdown of nutrients, only then we may be able to apprehend as how and where we should apply our efforts to reduce consumption.
Equation of energy
It is a very simple and straight forward equation. Anybody can understand it:
Energy stored = Energy intake – Energy used
If the value of this equation is negative, there will be no extra storage plus the use of the stored energy occurs. A positive value will always mean that energy will be stored inside the body.
Very simply put, if your intake is more than what you are spending, it will be stored within your body, in the form of fat, the ultimate form of stored energy in animals. So according to this equation, weight loss can be a very simple phenomenon, i.e. just keep your expenses more than the intake and the first thing that comes into our mind is exercise. Theoretically, if we go on using up our intake in the form of exercise, it should lead to a weight loss, but it doesn't work as simply as it is seen. The equation can’t be wrong, it’s a mathematical fact, how can it be wrong, then where the fault lies which needs to be addressed. That is why I put cumbersome and complicated metabolic facts above to make you understand what is coming after this.
A normal person having normal physical work done, i.e. usual routine activity and no extra exercise, will take 3 meals a day. You take a good breakfast at 7:00 a.m., say, an egg, some toasts, jam, and/or coffee or tea. Then off to work and without eating anything till your lunchtime at 1:30 p.m. For lunch, you chose to eat a moderate meal composed of balanced carbohydrates, proteins, and fats, as you still have to work till the evening and you think, it will be difficult on an “empty” stomach. Usual activity will go on till the evening when you return home and take a small to medium super at 9:00 p.m. and then off to bed at around 10:00 in the night.
If you are that person, even on such a nominal diet, you will be continuously increasing a very slight amount of weight on daily basis, say around 10 grams a day (which is the smallest gain I have chosen). After about 1000 days (3 years roughly), you have gained 10,000 grams or 10 kilograms (22 pounds). Imagine, three years back you were just 60 Kg and now your weight 10 Kgs more, i.e. 70 Kgs.
As you seem to be a reasonable person, you decided to start exercise in the morning, to increase your expenditure on energy. Though exercise is beneficial for your health, astonishingly, your weight gain graph is on the rise. You increase your exercise level, and the weight gain increases further. Most of the time, it so discourages people, they quit doing exercise or just stop thinking of weight loss ever. The problem getting from bad to worse.
In my opinion, the main cause of the decreased commitment is a lack of knowledge and handling the problem totally on wrong footings. Let’s first understand the muscle metabolism during exercise.
Exercise increases muscle metabolism tens of folds, and not only skeletal muscles, but other body organs also increase their metabolism several folds, for example, heart, lungs, brain, etc. for simplicity, we will just take skeletal muscle, as we all know these are the tissues which are active during any exercise.
As discussed earlier, a muscle will prefer utilizing glucose for energy production. If insulin is there, more and more glucose will be pushed inside these cells. Most of it will be stored as glycogen in non-exercising muscles, the ultimate form of glucose storage in all animals. When blood glucose level drops, as between the meals, and there is no insulin, glucose cannot now move into skeletal muscle (SM) cells. These cells then have to rely on the stored energy at first, and later use fats and amino acids for energy.
A piece of important information about exercising muscle is that they do not require insulin for glucose intake and hence glucose can easily pass from the blood to the inside of exercising SM cells. When you start exercising, the internal energy stored within an SM cell depletes quickly, more energy is provided by liver glycogen breaking down to glucose and releasing in the blood. Even in the absence of insulin, SM cells take in this glucose and burn it for energy. If you continue doing exercise, these reserves will also be diminished. The second most effective and efficient way of energy is the stored fats. Fats are broken down by the activated sympathetic system as well by the release of certain hormones during the exercise. In the SM cells, fats are directly broken down into energy and releasing a lot of ATP (adenosine triphosphate – the energy currency of the body). Burning of glucose and fat leads to the release and accumulation of certain acids, which contribute to exercise fatigue. These acids, especially lactic and pyruvic acid, should be either further metabolized by SM cells or should be taken by the flowing blood away from these cells to let SM cells work more efficiently.
So far so good, this means we can burn our stored energy either in the form of glycogen or fats and hence can put the energy equation into negative. But, further understanding of exercise physiology will give us the answer as to what happens next, which leads to reciprocal results of energy equation contrary to what was expected.
When you have stopped the exercise, the whole body, and especially SM cells are in a state called “energy debt”, and not only energy but oxygen debt as well. Oxygen debt will be easily paid by breathing heavily and deeply for some minutes even after the exercise is stopped. The energy debt, on the other hand, is a separate thing. It takes hours or even days to replenish the energy debt of SMs as compared to minutes for the correction of the metabolic system and washing away the waste products of exercising metabolism.
Not only SM but all parts of the body involved in the exercise will now require more amount of energy just to pay this debt. SMs will draw more energy to replenish all the stores and the metabolic debt occurred during the exercise. This will lead to a strong urge to get energy. Theoretically, one can argue that these debts can be paid for by the stored energy in the form of fats, but once the body realizes that the person is in debt, it refuses to give away these stores. The only solution to get energy is from outside and hence intake increases. The energy equation, once again, jumps back to a positive value, despite a lot of effort in place.
So, what to do effectively to reduce weight?
Rest assured that by writing this post, it is not the intention that you don’t give any consideration to a normal exercise. Exercise is by far the most important aspect of healthy living. Multiple studies have now shown that people who maintain appropriate body fitness, using judicious regimens of exercise and weight control, have the additional benefit of prolonged life. Especially between the ages of 50 and 70, studies have shown mortality to be three times less in the fittest people than in the least fit.
As discussed above, most people put their concentration on the second part of the equation, and ignoring the most important aspect of it, “the intake”.
If you want to jump into a healthy lifestyle, do not just blindly start with exercise without ever thinking of what sort of usual activity are you up to, and secondly what is your intake. If you love to keep your weight in a healthy range, there is no panacea other than to decrease your intake and then keep it to a minimum.
It was a popular belief that breakfast is the most important meal of the day, well it is not. It is proven now that it is just a myth, which is inserted into our minds by the so-called lobbyist of breakfast meals. I can go into details of this, but unfortunately, this is not the topic of today’s discussion, if interested, I encourage you to go through this article.
Before you even think of reducing intake, you have to get rid of the following food items for the rest of your life. If you are committed, do not give it a second thought, just do it:
All sugary soft drinks, including fizzy drinks and fruit juices with added sugars.
All confectionaries and bakery items.
High-fat meals or items.
All sort of red meat
Fast food items
Chocolates, toffees, and other attractive sweets
Always take into account your daily activity before you can manage a balanced intake to keep the energy equation negative. Suppose, you are an office worker, where you have to just sit, type, or shuffle the pages. You just have to get up a few times during your workday and not much physical activity is involved. If the same is the condition back home where most of the work is already done by paid personnel and you just have to cook for yourself etc. then you have to reduce your intake way more than a person, who has to do lot more activities not only at work but at home too. It is you who will decide how much I have to intake compared to my expenses. In our example, I will take two kinds of people, viz. the first one (P1), with mild daily activity, and the second one (P2), having moderate normal routine activity.
A word of advice will be that do not opt for any kind of exercise in addition to your normal activity if you are seriously thinking of losing weight. Exercise will come later in the way.
To start with, after getting up, P1 should skip the breakfast altogether, if need may arise, taking some fruit or a cup of unsweetened coffee will be sufficed. P2 may take a small amount of breakfast consisting mostly of cereals, milk, fruits, and/or coffee. Both will avoid any pancakes, eggs, toasts, etc.
Try avoiding a lot of activity at this stage other than your usual activity, which you should not decrease, true for both P1 and P2. After about, 2-3 hours, hunger will become strong and will increase in intensity as time passes. Remember, we have to achieve our goal to switch our body to a low-calorie intake whilst trying to keep our metabolism at a normal level. The physiology of this regime for the first week will altogether be different compared to the days ahead.
As you have not taken any meal during breakfast, either a very small amount of insulin or none is released. In the absence of insulin, SMs are forced to use fats for normal metabolism. As you are not exercising, just doing normal activities, your body is not going into energy debt. The constant stimulus of the body asking you for energy, in the form of hunger, will, of course, be there and will be cumbersome for a week. Remember, you are a committed person and you have to bear with it. Compare this to peeing. If you have the urge to pee, only you can relive yourself. Whatever you do, whoever you are, how influential may you be, doesn’t matter how many friends you have, it will be you who have to pee, nobody else can pee at your place. I know this analogy is a bit degraded, but I can’t think of anything else to make you understand better than this. When hunger strikes, it will strike hard, it will be you and only you standing against it. Nobody can assist you in this. This is your matter with your body. Stand tall, face the hunger, tell yourself, you can do it. The worse challenge during weight-loss is to stand against hunger.
When you are hungry, and no more nutrients are coming from your gastrointestinal tract (GIT), several hormones will be released to combat a drop in the blood glucose level. If all of your systems are normal, there is nothing wrong with it. No harm can come to your body, under normal conditions, by not eating. The foremost effect of these hormones will be to increase blood glucose levels. To achieve this, the liver will release glucose into the blood by breaking down stored glycogen. Recall that neurons will only use glucose for energy. As in the absence of insulin, SMs and other cells can’t get glucose, so they are forced to switch to fat breakdown. The hormones released when you are hungry, will force fat tissues to breakdown fats and release them in the blood, the fat cells cannot refuse the order of these hormones. These fats are easily taken up by all cells and used up for energy.
Besides, the liver can convert this fat into glucose and release it into the blood to maintain a normal level for neurons. Burning of fats leads to the generation of ketone bodies, but don’t worry, these can be easily dealt with by insulin. You can argue that insulin is not released during hungry status, but remember the longer-lasting effect of insulin even if it disappears from the blood (a topic of another post). Normally ketone bodies do not accumulate and not harm the body, as most of them can be converted back to glucose by the liver, and/or metabolized by muscle cells and even by neurons. That’s right, in addition to glucose, neurons can efficiently metabolize ketone bodies for energy.
As long as you can fight with your hunger, the body's metabolism is converting from a continuous and abundant supply of energy to a meager and exact amount needed for a perfectly normal requirement.
When comes lunchtime, you can have a moderate amount of healthy meal. Try to include as much balance ingredients and removing high energy items from your lunch. The amount of lunch must be less than what you usually take. This is important to tell the body to adjust itself to lesser and lesser energy coming to it. This will be the only meal you will receive until this same time next day.
This is why I asked you not to exercise these days. Just go on with your daily routine activities and that’s it. When you have won the hunger demands, now you can go for increasing physical activity, but not a rigorous exercise. If you can, do walk or cycle to your workplace. Even in the office, try increasing your activity by moving around, doing most of the work standing up (if you can). Walk or cycle way back home. Try to do your house chores yourself. Do not lose the magical mantra, i.e. keep your intake the same. It will take you some time, say a month or so before you will be well adjusted to this routine. The major change you should have noticed by now is that you have started to lose weight, and the amazing thing about this kind of loss is that it will be more or less permanent. This weight loss will be slow, don’t get discouraged. We are achieving the goal of permanent weight loss, that should never come back. We are trying to change our habits of intake so that later we should not fell into the trap of “delicious” hearty meals.
Calculate your BMI, and make a goal of perfect weight you want to achieve. Stick with this policy of decreased intake and slightly increased expense and you will achieve your goal in no time, depending upon how much you have to lose.
When you have achieved that, set this as a normal value. Now you can start exercising, as much as you wish. Remember to balance the expense with the intake and not the other way round. A good way to judge it is to weigh yourself every day when you wake up, after the bathroom, without in-taking anything. Keep that weight as a basal value. Any increase in it, albeit small, and you have to decrease intake that day.
You will be amazed to know that sticking to this formula will seldom lead to an increase in weight back to where you have started. Always tell yourself, I have to check my intake and not the expense.
Please let me know if you want to know any further or you have any questions about this.
Guyton and Hall Textbook of Medical Physiology twelfth edition. Pp 1065