In order to appreciate the process of weight loss we must have some understanding of the physiologic mechanisms involved.
I am going to explain as clearly and briefly as I can what weight loss is and whether or not it has a positive or negative impact on our health. I apologize ahead of time for the textbook-like nature of some of the information I am presenting, but in order to help you with your weight loss goals I believe some general groundwork must be laid. Obviously weight loss is the reduction of mass composing our body. This is measured by a scale, although this measurement does not tell us exactly what the weight we lost was composed of.
Our body is composed primarily of water and protein. There is also a significant amount of fat, gas and mineral composition. There is a lesser amount of carbohydrate, and a minute amount of vitamins and other various acids. So, our weight loss could take many forms. It could be a loss of actual tissue, or it may be a loss of energy stored as fat or carbohydrates. It may be a loss of waste such as fecal matter or urine, or it may be a loss of the water held within the cells, in the extracellular space or in the blood stream. Considering the multiple forms that weight loss can take, we must consider what it really means to our health. The effects on our health will depend on what weight we are losing.
What happens when I eat less? Won’t I lose weight?
When we use stored carbohydrates and fat in order to provide a large portion of our energy due to a drop in blood sugar, we may lose some weight. However this is typically a very small and temporary loss. As soon as we eat, the body has mechanisms to immediately replace the fat and carbohydrate stores. If there is a significant nutritional deficit with respect to calories or carbohydrates, we will use fat stores and tissues comprised of protein for an increasing percentage of our energy needs. This reduction of the carbohydrate reserves will slow in order to conserve the needed sugar for the brain. Essentially, when we experience states of starvation, we begin to break down vital tissues in our bodies to supply our energy needs. One of the detrimental aspects of this tissue breakdown is the over production of lactic acid, and the release of lipoproteins (a part of the tissue’s composition). In excess, these substances burden the body. Clearly, if this situation is prolonged, even on a modest level, it is not healthy. By starving ourselves, we limit our body’s ability to function optimally, which leads to a downward spiral in terms of our metabolism. Our bodies go into life-preservation mode, causing our metabolisms to slow down, making weight loss harder and harder.
Stress will increase fat use and may result in weight loss, but the cost is not worth the reward.
Most of the time when we want to lose weight, we really want to lose fat. Burning fat for energy is often induced by stress. While in a fasting state, whether by nutrient deprivation or over-exercising, our use of fat will increase. However, there are serious health impacts to be considered. Over the long haul, this stress-induced fat use will impair important metabolic organ function, resulting in a reduction in caloric need, and we may find ourselves unable to lose weight even at very low calorie intake. This occurs when a large percentage of our energy comes from stored fat. Even if a large percentage of our energy comes from fat for a short time, it will interrupt our body’s function in negative ways. For one thing, our bodies immediately replace the fat we have lost during this starvation state. Additionally, the byproducts of fat metabolism (free fatty acids and lactic acid), will affect the cell’s ability to appropriately use sugar and may compromise the liver’s ability to perform important tasks as it deals with these substances in the blood. Some experts believe that over extended periods of time, these conditions can create metabolic disorders that are rather difficult to reverse.
The key is moderation, working within the body’s comfort zone.
When we use stored energy from our fat cells (adipose tissue) in a non-stress state, our natural functions remain uninterrupted. Our liver will detoxify without compromising our body systems. We will find some health benefits in the reduced fat storage. One reason our body stores fat is to remove toxins from the blood. Also, we will reduce estrogen and other inflammatory hormones that are produced by the adipose tissue. The inflammatory products of fat tissue are over-synthesized in a stressed state, which is further reason not to try and lose weight too quickly.
Sometimes what we are losing is not tissue at all.
There is often unnecessary accumulation of mass that is not a part of our physiology in any productive manner. If we are talking about weight loss as a result of detoxification or removal of waste products (fecal matter and urine) from the body, this is a natural occurrence, and there will be some normal fluctuation in body mass. In some cases, however, waste products build up due to a less than optimal function of our digestive and detoxification systems. This commonly occurs when metabolic function is suppressed.
Losing the water contained in your tissues and blood can be perfectly normal and healthy. For example, a reduction in hyper-hydration of the cells due to swelling is a sign that inflammation is relieved and appropriate metabolic activity can return. Due to a “leakiness” of the vascular walls water can become displaced and is inappropriately located in the space between your cells. If this water is recovered by the blood and removed, this is a sign that a significant systematic stress has been relieved. On the other hand, a loss of water could be unhealthy. During a dehydration, the cells will shrink, reducing their ability to function, eventually causing death. A change of blood volume significantly affects our bodies’ ability to transfer nutrients and continue to feed the cells their needed sustenance, so it is important you consider the balance of fluids within your body.
In conclusion, it is important to understand that weight loss is just a number on the scale. That number does not really tell us anything specific about our body other than we now have less mass.
Weight is a crude measurement that tells us nothing about whether the change in body mass is from a healthy or unhealthy process. Whether the loss has come from water, protein, fat, or waste products doesn’t show up in a number on a scale, but these differences count and determine whether the weight loss will affect your health positively or negatively. For this reason, better measurement of progress than simply stepping on a scale will need to be outlined according to the underlying desire for weight loss.
In my next blog I will discuss in greater detail weight fluctuation during the process of improving health.
Resources:
Stress sensitivity increased during caloric restriction: http://www.jneurosci.org/content/30/48/16399.full.pdf
HPT down regulation do to fasting: http://www.ncbi.nlm.nih.gov/pubmed/18225975
Study exploring the multiple mechanisms of fat use and storage regulation: metabolic homeostasis is represented by tightly controlled stored fat use and replenishment: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1865564/
Free fatty acids play a role in insulin resistance: http://www.ncbi.nlm.nih.gov/pubmed/10354364
Body fat recovery increased by caloric or carbohydrate restriction: http://www.fasebj.org/content/22/3/774.full.pdf
Basic gluconeogenisis: http://en.wikibooks.org/wiki/Principles_of_Biochemistry/Gluconeogenesis_and_Glycogenesis
Gluconeogenisis and fasting: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC507441/pdf/980378.pdf
Exercise induced gluconeogenisis and hypoglycemia: http://www.ncbi.nlm.nih.gov/pubmed/2645124
