I have never seen something as effective as the Paleo Diet in terms of turning around health challenges and helping people to lose weight. However, I never see anyone get their ideal body or health without tending to the other 3 variables. It seems that people feel that they can sit around all day long and go to the gym 4-5 days a week for 90 minutes at a time and expect that to get them from point A to B perfectly fine. It doesn't work that way, your body operates under the authority of your genome, and there are certain environmental conditions that will help you lose weight, and others that will prevent you from losing it. Today we look at physical activity and how it can help you to lose weight.
Fat burning-The only way to lose weightWhen we are trying to lose weight, what we are truly trying to do is burn fat. Before we talk about how you burn fat, let's define a couple of key terms in the process. Triglycerides (TGs) are basically just fat. TGs are the way your body stores fat, but TGs are also found in the blood once fat has been released from storage. To release TGs from storage, the hormone glucagon signals an enzyme called Hormone-sensitive Lipase(HSL) to release free fatty acids from your fat stores. We all know that water and oil don't mix, so in order for TGs to be carried in your water-based bloodstream, they are reassembled in lipoproteins that can carry them to target tissues such as muscles to be metabolized. Most of us confuse lipoproteins with cholesterol as the terms LDL-C and HDL-C are typically used to refer to cholesterol by physicians. However, these are lipoproteins that carry cholesterol, not cholesterol themselves.
In order for TGs to be broken down, you need the enzyme Lipoprotein Lipase (LPL) to break them out of the lipoprotein that caries them in the bloodstream so they can enter cells to be used for energy. What we typically see in people with Type 2 diabetes (T2D) is high levels of blood triglycerides, at least Caucasian people with T2D. African Americans with T2D don't have high TG levels, and this is directly related to LPL activity. In Caucasian people with T2D, insulin resistance impairs LPL activity leading to elevated TGs in the blood (1). African American people with T2D, however, do not have high blood TGs because their LPL activity is not impaired by insulin resistance (1). This phenomenon explains why blood TG levels and TG:HDL ratio can predict insulin resistance in Caucasian males but not in African Americans(2). This does not mean that African Americans cannot become obese, even if LPL breaks a TG down in to it's component fatty acids and glycerol, you still need to burn those components or they will just get restored as TGs in fat tissue.
How to lose weight with NEATLet's get a handle on all of that science so we can understand how this information can help us lose weight. The hormone glucagon signals HSL(Hormone-sensitive Lipase) in fat cells to breakdown TGs in to their component fatty acids and glycerol so that they can leave the fat cell and enter lipoproteins where they are reassembled back in to TGs that carry them to target tissues, particularly muscle, via the blood. When the TGs reach the target tissues, they need to be broken down by LPL (Lipoprotein Lipase) so that they can enter the muscle cell to be burned for energy, otherwise they will get sent back to fat tissue for re-storage. As you can see, LPL activity is very important for the proper breakdown of TGs that are released from fat cells so that they can enter muscle cells to be metabolized. So how do we increase LPL activity so that this can happen and you can lose the extra weight?
In order for LPL to be activated, a muscle cell must be activated. During muscular contraction, HSL and LPL are activated at the same time within the muscle cell(3). The HSL within the muscle cell is used to breakdown TGs that are stored in the muscle cell while LPL is sent to the capillary beds that supply the muscle with blood to breakdown the TGs that are sent in lipoproteins from fat tissue. In addition, their is LPL made in the capillary beds that also help breakdown TGs so they can enter muscle cells. Recall from our discussion here that Type I muscle fibers are best equipped to burn fat and therefore have higher LPL activity. This is important to note because Type I muscle fibers are recruited for all types of activity while the Type II muscle fiber types are only recruited for high intensity activity.
It appears that getting regular low level physical activity is more important for health and LPL activity than getting regular intense exercise(4). Inactivity rapidly reduces the amount of LPL produced by a rate much greater than intense exercise can make up for. In fact, getting regular low level physical activity and performing intense exercise appear to have separate mechanisms by which they improve LPL activity and health(4, 5). Studies in rats have shown a 90-95% reduction in LPL activity in limbs that are restricted from muscular contraction (6)
When looking at NEAT and intense exercise time, it's not terribly difficult to see which one is a more important factor in how you lose weight. Given that a week has 168 hours and the most avid exerciser will probably top out at 12 hours of intense exercise per week(7% of total weekly hours), NEAT is where the bulk of your weight loss efforts should fall. Of the variables that affect energy expenditure, NEAT is the most variable in that a sedentary person will burn 15% of his or her daily calories through NEAT while an active individual can burn upwards of 50%(7). Couple this with the improved LPL activity and you will be a fat burning machine. It's ironic that most people worry about eating 5 times a day when trying to lose weight given the fact that the thermic effect of food only accounts for 10-15% of total energy expenditure, talk about putting all of your eggs in the wrong basket.
Factors affecting NEATThere are a host of factors that will subconsciously affect NEAT, and thus your ability to lose weight. The weather and seasons have an effect on NEAT, as does your occupation(7). Increasing caloric intake tends to increase NEAT while decreasing caloric intake tends to reduce it. Anecdotally, I have found that clients who work in enclosed areas also tend to have a much lower NEAT and NEAT also tends to decrease the day of and following an intense workout. As mentioned, we measure NEAT with a Fitbit activity tracker which helps to keep NEAT where it should be by making clients conscious of it and helps determine the amount of NEAT a person needs to help them lose weight. We look at more data than the total number of steps, but for most people daily steps is sufficient enough to give them an idea of how much NEAT they need to lose weight. For the first few days we have clients wear the Fitbit and not attempt to increase NEAT so we can get an idea of where we should start them as well as how big of an impact a lack of NEAT has had on their stalled weight loss efforts.
ConclusionWhen trying to learn how to lose weight, you need to focus on all 4 of the primary variables associated with weight loss before you even begin to worry about exercising. Your goal for each variable is to make sure that each one puts you in a position to burn fat. You want to send the proper signals to your body that your goal is to lose weight and you want to put your internal environment in to a position that will utilize the fat you have stored from excess/improper food consumption, sedentary behavior, poor sleep, and poor stress management to do that. From a physical activity perspective, this includes spending as little time sitting as possible as well as increasing Non-exercise activity time(NEAT) so that your body will continually metabolize fat, this is how you lose weight. Without consistently high levels of LPL to help breakdown fat so it can enter your muscles, you will not be able to lose weight. You may see the number on the scales move, but all you will be doing is shifting hydration levels and/or catabolizing muscle. Neither one of those is an effective long term strategy to lose weight.
If you have a Fitbit and would like to get involved with some challenges to increase NEAT, "like" our "Synergy Wellness Program" facebook page and you can get involved in some of our challenges. If you'd like to buy a Fitbit, they can be purchased at Best Buy or online at Fitbit.com
In part 6 of this blog series we will discuss the role sleep play in teaching you how to lose weight.