Tag Archives: Muscle

Weight Loss – Myths and Half Truths

Disclaimer: The author is not a qualified medical professional. Readers are advised to exercise caution and seek professional opinion if they wish to act based on the following article.

Weight Loss Basics

Let’s first understand this simple weight loss arithmetic. Everything that we eat gives us energy; let’s call it calories (Kilo Calorie to be precise). Similarly, for everything we do (includes sitting or even sleeping) we spend energy or calories. If our input and output of calories is same our weight remains constant. If we consume more calories than what our body needs the excess calories are converted into fat which increases the body weight. Similarly, if our intake of calories is less than what our body needs, our body uses the body fat (a combination of fat and muscle to be precise) to meet the shortfall which reduces our body weight. Calorie deficit can be achieved by (a) consuming fewer calories (eating less); (b) burning more calories (exercising) or; (c) a combination of the above two.

Exercise to lose weight

In general, people believe that burning more calories is a better option than eating less. The common problem with this approach is that once people start exercising, they consider it a license to eat more.  While exercising has many other benefits, the calories burnt during most exercises are generally low to moderate and in most cases even these get neutralized by increased diet.

For example walking at 2.5 miles per hour pace for one hour burns 210 calories (for a person weighing 70 Kg) while just a can of Coca Cola (normal not diet) contains 207 calories. Other more rigorous exercises burn calories at a higher rate but since these are difficult to perform for a longer duration the net calories burnt may not be significantly higher. For example jogging for 25 minutes burns almost the same calories (214 to be precise) as walking for one hour.

The real issue is how does burning calories translate to weight loss? Most people don’t know the answer and often end up nurturing unrealistic expectations as soon as they start exercising.

The fact is that a net deficit of 7,700 calories is required to lose 1 Kg weight. This means every day walking one hour or jogging 25 minutes and without increasing the diet will take 37 days to lose 1 Kg weight. In practice, it is quite possible to miss the exercise at least once in a week and eat more at least once in a week. This would make it 47 days to lose just 1 Kg. Most people may actually miss the exercise more often as well as overeat more often and therefore it could take as much as 2 months to lose 1 Kg.  Also keep in mind that 1 Kg weight loss is not at all noticeable visibly in fact not even on the common weighing scale. That’s how hard it is to lose weight and therefore it is quite understandable why people get disheartened soon after starting an exercise regime.

Let’s not forget that exercising has many other health benefits and should not be viewed solely from weight loss point of view.

Dieting is Unhealthy

Let’s get it right, the main reason for obesity is overeating and unless this is corrected there is very little hope of getting back to shape. Secondly, as explained above, exercising alone will take a long time that too if done regularly and without increasing diet.

Most “Weight Loss Experts” would advise a highly complicated diet plan comprising of 6 small meals a day. While, it might work if you are able to stick to it, such complex diet plans are often impractical and therefore very difficult to sustain. Secondly, when you eat 6 (small) meals a day, you also have to resist the temptation of overeating 6 times a day.

A more practical approach could be to skip a meal – most convenient being the lunch. However, you have to keep in mind that the purpose of skipping lunch is to reduce your calorie intake and therefore this does not give you a license to overeat during breakfast or dinner or add a new meal like an evening snack.

A big myth is that if you skip a meal your body will go into “Starvation Mode” and will slow down the metabolism and hence you will hardly get any benefit of skipping meal.

Starvation Mode is not a myth but the way it is misused to scare people is wrong. The body does go into Starvation Mode but only when you are really starving. Starving here means when you stop eating all together. For all practical purposes, there is absolutely no effect on the metabolism rate and other functions of the body at least for the first 12-14 hours of fasting. Skipping a meal is definitely not same as starving. Initially the body may behave a bit erratically because it is habituated to receiving lunch at a particular time of the day. However, soon it would fall into the new routine.

Understanding the Role of Blood Sugar

Blood sugar is the source of energy for the body just like petrol is for a car. The body constantly needs the blood sugar level to remain above a certain threshold to continue to function normally. A large part of the blood sugar is consumed by our brain. In general, all hot blooded species (including human beings) need much more energy (as compared to cold blooded animals) to maintain constant body temperature. This explains why hot blooded animals can not live without food for a long time while cold blooded animals such as Crocodiles can live without food for months. Further, energy is also required to support all the physical activities of the body – both internal as well as external.

Barring a few, almost everything that we eat gets converted into blood sugar. The time taken between consuming a food item and its reflection on blood sugar level is different for different foods. Direct consumption of sugar in any form obviously has the quickest effect. Carbohydrates are next and fibers/ protein take the longest. The rise in the blood sugar is proportional to the amount and quality of food consumed. Typically, the blood sugar level will start rising rapidly around 30 minutes after a meal. As soon as the blood sugar crosses a certain level, the body releases insulin to manage it within the acceptable limits. The insulin converts all the excess blood sugar into fat and stores it for future use.

While our body needs almost constant supply of sugar, it is not feasible to consume food all the time at the required rate (except when a patient is put on glucose drip in the hospital). For an average human being the daily requirement is 1500-2000 calories. This means that our body burns calories at an average rate of 60-80 calories per hour. Normally, we eat at least three big meals – breakfast, lunch and dinner which reflects an average intake of approximately 500-650 calories per meal. At the rate of 60-80 calories, it will take around 8 hours to fully consume the calories of one meal. However, the body can not allow all the calories to remain available in form of heightened blood sugar level for that long. In fact, for a normal person, the blood sugar level is brought down to maximum acceptable high of 120-140 mg/dl within 2 hours of consuming a meal. The balance sugar is immediately converted into body fat. After reaching 120-140 mg/dl sugar level the body stops the release of insulin and hence further conversion of blood sugar into fat is also stopped. From 120-140 mg/dl level, the blood sugar continues to drop as the body draws energy from blood sugar. When the sugar level approaches the minimum acceptable level which is around 90-85 mg/dl, the body detects the low sugar level and send a hunger signal. This is when we feel the need to consume food to jack up the blood sugar. However, if we don’t feed the body at this point, the body starts using its fat storage to replenish the blood sugar. This is the phase when weight loss occurs. The actual process is even more complicated than this as the body has additional sugar storage in the liver and muscles which may be used depending upon the urgency of the situation. If we indulge in an activity which requires a faster replenishment, the body will burn muscle mass along with fat in order to match up to the higher burn rate. In extreme (life or death) situation when a reflex action is triggered, the muscles use their internal glucose storage as drawing from the blood sugar takes time. This will happen even when the blood sugar level is sufficiently high. Similarly, even when there is no reflex action involved but the body detects that fat and muscle burning is unable to maintain the blood sugar level above the critical level, the liver releases its internal glucose storage into the blood which boosts the blood sugar level all of a sudden. This action is called “Liver Dump”. Typically this happens during the night as the process of conversion of fat into sugar is comparatively much slower during sleep. However, the Liver Dump can also happen if we indulge in a physical activity which burns blood sugar faster than what the body can produce by burning fat and muscle. The Liver Dump generally elevates the blood sugar to a much higher level and till the sugar level comes back to 85-90 mg/dl range further fat burning is stopped. However, the emergency reserves of muscles and the liver get the first priority for replenishment at the first available opportunity that is as soon as we consume food.

Aerobics and Fat Burning Zone

The so called Fitness Experts have built big theories of aerobic exercise regime for optimization of fat burning. They have tried to associate the rate of fat burning with the heart beat rate. Once again, it may not be entirely incorrect but this is certainly a half truth.

Firstly, the heart beat rate has no direct correlation to the rate of fat burning. Only blood sugar rate has a direct effect on fat burning. As explained above, the body decides the ration of fat and muscle burning depending on the rate of replenishment required. At very low rate, the body will burn mostly fat and very little muscle. However, as we increase the intensity of exercise and as our blood sugar level comes dangerously close to the minimum acceptable level, the body starts drawing more and more sugar by burning more and more muscle. The Fitness Experts link the heart beat rate with the intensity of exercise and come up with various approximations for fat to muscle ratio. This may work in normal situation but not when someone starts off with a high blood sugar level which may be due to insufficient gap between meal and exercising, or in case of a diabetic person or if a Liver Dump happens during the exercise.

In any case, as mentioned already, the calories burnt during physical exercise are not that big (300-400) and this in itself would account for an extremely small weight loss (remember 7,700 calorie deficit = 1 Kg weight loss). For such a small weight loss, the ratio of fat and muscles burnt is not that big a concern.

Further, the loss of muscle is not permanent and most of  the lost muscles are restored subsequently. We must keep in mind that for a certain age the muscle mass in our body is mostly need based and depends upon how much we strain each muscle. Therefore, even if some muscle mass is lost to replenish the blood sugar level, it is subsequently restored if we consume enough protein. Our body uses protein to repair and build muscles and this is normal routine process.

This blog post has become much bigger than what I had anticipated and there is still so much to write about. However, I will resist the temptation and end this post here considering specially the limitations of the readers to maintain interest as well as absorb the information in one go.

I would try to come up with a sequel post on this topic in near future.