The Science of Fat Loss Part 4 ~ Long-Term Weight Loss
In the first three parts of this series, I’ve talked about different types of body fat (part 1), how the body breaks away fatty acids from the fat cell (part 2) and finally how the body uses the fat that it broke away from the fat cell (part 3). In this last installment, I’m going to touch upon the long-term maintenance of fat loss and why for some individuals it can be an uphill battle.
Two of the Four Factors for Long-Term Fat Loss
Of all the things that control long-term fat loss, hormones, both total amount and cell sensitivity, are one of the major keys in determining whether or not it will be easier or harder for you to keep the fat off.
Another factor in determining whether or not fat loss will be easy or hard for you is the total amount of fat cells you have to begin with. In general, the less fat cells you have the easier it is to keep fat off the fat off. This is due to two things:
1 – Fat cells are good for one main thing – storing energy to be used later on.
2 – Besides visceral fat, the fat cells you have are the fat cells you will have for life (unless you have liposuction).
Therefore, the more fat cells you have, the easier it is for you to gain fat and the harder it will be for you to lose fat overall, especially in the long-term. This is also one of the main determinants in how quickly someone will lose fat compared to someone else.
The Main Hormone
So say, you’ve been on a diet and working out for about 6 months now. During this time you’ve lost over 10% of your bodyweight and have noticed some improvements in the way you look, the way your clothes fit you and the way you feel. Congratulations! Now all you have to do is keep it off for life.
You see, most people who lose over 10% of their bodyweight will go back to gaining it all back. In fact research has shown that over 8 in 10 people that lose a significant amount of weight (5% of your bodyweight is “significant”) will end up gaining it back within a year.
Why is this and what can you do about it?
One of the major players for long-term fat loss is the hormone leptin. Only discovered in 1994, leptin is released from fat cells and acts as a thermostat to tell your body how much fat you’re losing/have lost. In other words, it acts as an anti-starvation hormone and in terms of evolution has allowed the human species to thrive in times of low food intake.
It does this in healthy individuals, by your fat cells releasing a certain amount of leptin hormone based upon how much you’ve been eating. Therefore, if you’re eating at maintenance calories (aka, you’re not over-eating or under-eating), then leptin levels are humming along at we’ll say 100% of normal output. If all of a sudden you go on a diet, your leptin levels will drop dramatically (say to 60% of normal output) and will not necessarily match the amount of fat loss you’ve incurred. In other words, leptin levels will drop quicker than fat loss.
The lowering of leptin levels then tells your brain to slow down the release of thyroid hormones, which in effect, slows down your metabolism. It also stimulates the release of hunger hormones, and in particular the hormone ghrelin. This hormone stimulates your appetite and you’re hungrier than normal. If you continue on the diet, then your body will keep leptin levels in order to keep your metabolism slower, so you don’t starve to death. It does this by slowing down your metabolism.
What is a ‘Slow Metabolism?
So what does a “slower metabolism” entail? It means that you’re burning less calories, but the question is why? There are two simplistic concepts:
1 – You are burning less calories at rest.
2 – You are moving less overall.
Burning less calories at rest is directly related to your thyroid hormone output, which determines how “hot” you burn or how many calories you burn just sitting around. Research has shown that while on any diet your thyroid levels will go down, and therefore you will burn less calories at rest. Usually this plays a part in weight re-gain, but isn’t the most important part in the equation.
The other aspect comes down to moving less. You see we all have an amount of movement that we make daily, without necessarily thinking about it. Researchers call this movement Non-Exercise Activity Thermogenesis, or NEAT. What this means are the small movements we make every day, without conscious decision making slow down and this slow down decreases the total amount of calories burned by a significant number.
For someone that has lost over 10% of their bodyweight and kept it off, the total amount of fewer calories burned from a slowdown in their metabolic rate (first reason) totals about 150 calories, compared to someone that is naturally thin. On the other hand, the decrease in NEAT calories (second reason) burned by someone who has lost over 10% of their bodyweight totals about 300 calories less per day. The graph above shows those numbers.
So if you look at the factors contributing to weight regain, you’ll see 4 main things working against the person who’s lost a significant amount of weight:
1 – Generally a greater number of fat cells, which make it easier to add fat.
2 – Lower Leptin levels which increases appetite regulating hormones.
3 – A slower metabolism overall, totaling about 150 calories less burned per day.
4 – Less NEAT movement totaling about 300 calories per day.
What Can You Do About It?
If you’ve ever heard a good personal trainer talk to a client, you have probably heard something to the effect of, “You need to make eating healthy and working out a lifestyle.” In fact the phrase is so pervasive it’s cliché.
The truth is that despite its “cliché-ness” it’s the truth. You see, the fact is you can’t change the amount of fat cells you have, but can ensure that you don’t fill the ones you have by continuing to eat a healthy diet. Lower leptin levels will increase your appetite by stimulating certain neurotransmitters, but you can combat that by eating healthier foods which help to control your hunger hormones in your brain.
A slower metabolism and less NEAT movement can definitely be a pain to deal with, but this is why exercise, although not the most predictive factor in short-term weight loss, is absolutely essential in long-term weight-loss maintenance.
In fact, a huge percentage (94%) of those that have kept a significant amount of weight loss over a year’s time exercise almost daily. If your body is subconsciously having you move less, then you have to consciously choose to move more. It’s just that simple.
The short answer of what you need to do:
1 – Exercise, in particular strength training – Over time this should help with making you more sensitive to the hormones you have, while helping to increase your overall metabolic rate.
2 – Exercise, in particular, cardiovascular exercise – This should help curtail the total amount of calories you’re not burning daily from the NEAT activity.
The total of these first two steps should total about 2500 calories per week.
3 – Eat a whole-food diet, based upon healthy principles – More protein, more vegetables and healthy fats with about 100-150 grams of carbs per day from healthy starch and glucose sources such as rice, sweet potatoes and an occasional piece of fruit.
4 – Get Good Sleep – Sleep deprivation has been shown to increase hunger, which if you’re already on an uphill battle with controlling hunger (lowered leptin levels) makes this even more important.
These four steps, although not “revolutionary” truly lay the foundation of long-term weight-loss and health. I hope you realize that although the Science of Fat Loss may not be simple, the foundation towards fat loss can be.
Have questions? Leave a comment below.
1 – National Weight Control Registry: http://www.nwcr.ws/
2 – Long-term weight losses associated with prescription of higher physical activity goals. Are higher levels of physical activity protective against weight regain? ~ http://www.ajcn.org/content/85/4/954.long
3 – Long-term persistence of adaptive thermogenesis in subjects who have maintained a reduced body weight ~ http://www.ajcn.org/content/88/4/906.full