We store fat in adipose tissue in our bodies — mostly under the skin (subcutaneous) or in the body cavity (visceral), with a small amount in our muscles (intramuscular).
Why is fat loss so important?
We need to lose fat…
As a group, people in most industrialized societies are likely to be over-fat.
This isn’t just a cosmetic problem. Excess body fat can negatively affect nearly every facet of life, including:
- decreased mobility
- poorer emotional health and self-esteem
- increased risk of organ failure
- poorer circulatory health
- increased risk of heart disease
- increased risk of stress fractures
- increased risk of strokes
- increased risk of cancers
- decreased sexual and reproductive health
Fat cells can act as endocrine factories and produce hormones that influence numerous processes in the body — most of which lead to more fat accumulation.
Beyond the health of it all, carrying a lower body fat is often considered more attractive and desirable as the underlying muscle tone is revealed.
Further, carrying a lower body fat is advantageous for many sport competitors (barring sumo wrestlers) as extra fat weight adds drag and additional resistance that must be overcome.
Bottom line: Carrying a lot of excessive body fat makes health, body composition, and athletic performance worse.
…but it’s hard.
Here’s the problem — collectively, we’re not very good at losing fat either.
About 95% of those who are overweight go on repeated diets, only to gain most or all of the weight back within one year. Nearly 70% of the United States is overweight or obese. The percentage of 12 to 17 year olds who are overweight has doubled since 1980.
We need a better solution. Knowing how fat loss works may be helpful.
What you should know
Fat cells are a major storage site for body fat, and are in a continuous state of turnover. Fat metabolism is regulated independently by nutritional, metabolic, and hormonal factors; the net effect determines levels of circulating fatty acids and the extent of body fat.
Fat loss and hormones
Fatty acid release and use requires lower insulin levels and an increase of the hormones glucagon, cortisol, epinephrine, and growth hormone. These “anti-insulin” hormones activate HSL. The other major hormone that influences fat metabolism is thyroxine (thyroid hormone).
After a large feeding, glycogen is synthesized until stores are replenished. If high blood sugar persists, glucose is converted to fatty acids. Amino acids can also be converted to fatty acids. The enzyme necessary for cells to accept triglycerides is lipoprotein lipase.
In the un-fed state, insulin concentrations fall, and the anti-insulin hormones increase. This accelerates fat use.
Fat loss and caloric deficit
When we decrease our caloric intake significantly, the body preserves fat stores very efficiently. Since insulin is low, thyroid hormone production is decreased. With this, resting metabolism is lowered. This can take place within 24 hours of starting an extreme diet.
The body’s response to calorie deprivation makes rebound weight gain all but definite once the diet is finished. Muscle is usually lost, so the body usually becomes fatter.
Fats are more than just a fuel source during rest and lower intensity exercise. Fats restore phosphagens that have been exhausted during high intensity exercise. After intense exercise sessions, oxygen uptake is increased, which allows restoration to pre-exercise conditions (the “afterburn” effect).
Fat loss is a complex problem
With our focus on specific nutrients, intense nutrition counseling, dieting and processed food consumption over the past 30 years, body fat levels have also increased. In other words, more information, more dieting, more junk food has given us more fat.
While some of this may seem counter-intuitive, it illustrates the importance of body awareness, avoidance of processed foods, regular physical activity and influential food advertising.
Summary and recommendations
To maintain a low body fat and/or lower body fat:
- Exercise at least 5 hours per week
- Eat whole/unprocessed foods at regular intervals, while being aware of physical hunger/fullness cues
- Sleep 7-9 hours per night
- Don’t engage in extreme diets
- Stay consistent with your habits
- Incorporate non-exercise physical activity
- Ignore food advertising
For extra credit
Aspartame was approved for use in 1981, and while this non-caloric sweetener was hypothesized to help control body weight, since 1980, levels of body fat have increased….stop using, eating or drinking anything with this in.
Other factors associated with lower levels of body fat include:
- green tea
- low energy-density foods
- dietary protein
- avoiding refined carbohydrates
- adequate hydration
- dietary fibre
- fruits and vegetables
- regular exercise
- adequate sleep
- a supportive social network
While cortisol can break down muscle tissue, it can also break down body fat.
If you increase physical activity and nutritious food intake, metabolism will increase.
Blaming weight gain on calories is like blaming wars on guns. The diet is not the cause of excessive body fat levels. Rather, it’s the entire lifestyle.
Severe calorie deprivation inhibits the production of serotonin, a brain chemical needed to control appetite and maintain harmony with food.