In this post:
- Short term diet effects
- 3 Reasons for Plateaus. ie: Long term diet effects
- Why dieting can make you fatter
- Metabolism term cheat sheet
If you have ever dieted, which most of us would be in this boat, you know it is not easy in the first place. But, if you put your mind to it, it will happen. Especially if you are a beginner or are on the heavier end of the spectrum. Bigger changes happen more quickly.
As your fitness level increases and you become more advanced gaining more muscle or reaching lower body fat levels, getting leaner becomes more difficult. You can feel like the scale is an a$$ hole when you step on it in the morning and it remains unchanged. Even your progress pictures leave you disappointed.
Not only is fat loss something we strive for, but building and keeping muscle while dieting down is another. Muscle requires a lot of energy to build and sustain while it doesn’t provide much energy when broken down. This makes excessive muscle tissue less than ideal to maintain from a survival stand point. Naturally the body will build just enough muscle to carry out activities necessary for survival while maintaining a “set point” body fat percentage. While the paleolithic man had a great everyday figure, he or she wasn’t walking around like Arnold schwarzenegger or Iris Kyle.
As a natural bodybuilding athlete, dieting to super cut lean levels is a fight with your body to lose fat while keeping that hard earned muscle. No one wants to lose that sexy booty or swole shoulder caps.
The body is a perfectly coordinated machine constantly trying to maintain homeostasis. There is a fine balance of hormones and processes that keeps your body within the same temperature range, hydration level, energy storage and so on.
So what happens when we throw our bodies into a negative energy balance trying to get below 20-22% body fat for women or 12-15% for men? A whole lot of things. The following is a summary of the short story which is the summary of a long ass story!
The physiological reactions we will talk about are from the stand point of a typical cutting diet- moderate to low fat, moderate to high carbs, and moderate to high protein. See more in this article: Cut Phase: How Much to Lose and How to Cut Calories.
Before we get started, there is a little hormone cheat sheet at the end of the article you can reference for clarification...
Short Term Diet Effects
Initially, in the short term, your diet goes well, especially for those that are obese or beginners in the fitness realm.
Basically, a negative energy balance causes fat to mobilize from fat cells from a cascade of hormonal responses:
- Decrease in calories = lower blood glucose = lower insulin levels = mobilize fat from fat cells.
- Catecholamine release usually increases = mobilizes fat for energy preparing the body for physical activity.
- As a result of the changes, fatty acid levels are increased in the blood stream (pulled out of the fat cell) and used for fuel.
- The whole effect increases if you deplete liver and muscle glycogen. Many people cutting for a bodybuilding contest (this includes you bikini girls) will have low and zero carb days to use up glycogen (carbohydrate stores) so your body will utilize fat stores.
- The increase in fatty acids in the blood stream causes short term insulin resistance which spares glucose and promotes fat oxidation (fat burning).
So far so good… right… well, as you diet for longer periods of time and start getting leaner other things begin to happen…..In the end, the harder you push your metabolism, the harder is pushes back.
Long Term- 3 causes of diet plateaus
As you push your limits by doing more cardio and cutting more calories, your metabolism compensates. You start feeling hungry all the time, energy begins to suffer, and you feel cravings for sweet, salty, and fatty foods. Depending on individual responses, metabolism has now slowed down significantly or put on the brakes slowing daily calorie burn rate by between 200 and 800 calories per day.
1) Stressed sympathetic nervous system
Your nervous system is categorized into two systems, the symapathetic nervous system also known as the fight or flight system and the parasympathetic nervous system also known as the rest and digest system. These systems maintain a balance in your body and when that balance gets tipped to one side, the whole system is thrown off.
Dieting for long periods of time and doing an extreme lower calorie diet with continuous heavy cardio, which is commonly seen in a competitors routine, stresses the sympathetic (fight or flight) nervous system. This sends it into overdrive where it’s “stuck” in the on position and suppresses the parasympathetic nervous system. You may wake in the morning with a higher heart rate, experience sleep disruption, be more sensitive to bright lights, have lower motivation, feel fatigued, retain water and have digestive dysfunction like IBS, gas and bloating.
2) Hormone signals go into overdrive slowing your metabolism
Hormonal signals to the endocrine system sends the entire metabolism into overdrive overwhelming much of the regulatory balance, antioxidant/free radical balance, acid/base balance, blood sugar balance and so on. Your body will do its best to slow the metabolism to meet its energy intake and expenditure. Here’s a simplistic version of what happens with your hormones…
Leptin is secreted from the fat cells to tell your brain you don’t need to eat. When leptin secretion is low, this tells your brain you need to eat! This directly affects liver, skeletal muscle and fat cell metabolism.
Ghrelin, leptins’ opposing counterpart is the hunger hormone that tells you you need to EAT!
While this may mobilize fat, the insulin drop causes testosterone to bind more efficiently to SHBG (sex hormone binding globulin) lowering testosterone levels. Yes ladies, you have testosterone but much lower levels than men. Testosterone is anabolic (muscle building). This is why insulin prevents break down of the muscle. When insulin is low, muscle breakdown occurs more readily. (Also see Don’t Lift, You’ll Look Like a Man!)
As mentioned above, testosterone decreases. It can drop as much as 70-77%! This has greater adverse affects for the male than female due to females having much lower levels of testosterone to begin with.
Peptide YY (PYY) decreases
Secreted from cells in the gut, this hormone controls your appetite. When levels are low, your appetite will soar.
Cholecystokinin (CCK) decreases
Secreted from cells in the gut, CCK stimulates the digestion of fat and protein and acts as a hunger suppressant.
This is a big one. Cortisol, the stress hormone, is released from the adrenal glands in response to lifestyle and physiological stressors such as low blood glucose. This can cause increases in cortisol as much as 100%. Cortisol promotes protein breakdown (muslce loss), stimulates the conversion of protein to glucose in the liver (again, muscle breakdown) and raises blood pressure, blood sugar and modulates your immune system. Aside from promoting muscle loss, prolonged elevated levels promotes fat storage and decreased thyroid function among other hormonal imbalances.
Fall in energy state of the muscle hinders protein synthesis but increases FA oxidation (fat burning)
Good for fat burning, bad for muscle retention
Overall- protein synthesis (muscle building) is decreased and breakdown is accelerated.
High fatty acid levels impair the uptake of inactive thyroid hormone into the liver while there are also changes in the liver that hinder the conversion of inactive thyroid (T4) hormone to active thyroid (T3) in the liver. This negatively affects metabolism, blood pressure, and tissue growth.
Insulin like growth factor (IGF-1) decreases
Due to the changes in liver metabolism, decrease in IGF-1 hinders muscle building and growth hormone.
Growth Hormone (GH) decreases
Decrease in GH hinders muscle building effects.
All of the above are not ideal combo’s if you want to keep all that hard earned muscle you worked for during your bulk phase while trying to get lean! Whether you are a bikini girl or a physique female, keeping that booty or those fabulous quads is important for your competition.
3) Your body will always be hungry below the normal body fat range
When body fat levels are low the combination of signals sent by leptin, ghrelin, insulin, glucose, and a host of other hormones (cholecystokinin, glucagon, peptide YY and so many others) are all involved in hunger and appetite telling you you need to eat… feed me! I am starving! I need to survive! Your body doesn’t know you are trying to look like a fitness model or compete in a figure competition. Think you want to stay 10% or less as a female… good luck! It is possible but not easy.
Why long term dieting can make you fatter
Prepare to lay down the fat!
As stated above, your body is concerned with survival first and foremost. When you diet down, your metabolism will slow down and adapt to your diet and fitness level making it increasingly harder to lose weight. Many people fall into the trap of dieting down and then going right back to eating the calories they were consuming before dieting. Their now sluggish metabolisms (hormones) are not able to process all the extra cals for energy so the body just stores them on their bootay’s for some serious badonkadonk. So Check out: 7 Tips and Tricks to Bust Through Diet Plateaus
Metabolism Term Cheat Sheet
Energy Storage in the Body:
Glucose: sugar/carbohydrate. Stored in the muscle and liver in the form of glycogen. Glycogen is mobilized from muscle and liver cells into the blood stream to be used for energy.
Fatty acids: Fat circulating in the blood stream. Stored in fat cells (adipose tissue). Mobilized from fat cells into blood stream to be utilized as energy. Dietary fat you eat are triglycerides, which is a molecule of glycerol (a sugar) bound to three fatty acids.
Insulin– hormone that reduces blood sugar levels by regulating cell uptake of glucose (carbs). Also anabolic (muscle building).
Insulin sensitivity– meaning insulin will generate a large response in the body as the cells are very receptive to insulin.
Insulin resistance– meaning the normal response to insulin is reduced. Your cells are resistant to insulin and cell uptake of glucose is hindered.
Glucagon– hormone that increases blood sugar levels when energy is needed. Causes a release of glycogen (stored from of glucose) from muscle and liver stores to be used for energy.
Insulin like growth factor (IGF-1)– a hormone that has an anabolic (muscle building) affect and mediates growth hormone
Growth Hormone (GH)– hormone that stimulates protein synthesis (muscle growth).
Catecholamine- (norepinephrine and dopamine for example) Is a neuromodulator. Prepares the body for physical activity like increase in heart rate, blood pressure, and blood glucose levels with general reaction on the sympathetic nervous system. High levels in the blood are associated with stress.
Cholecystokinin– hormone that stimulates the digestion of fat and protein.
Leptin– the satiety hormone. Made in fat cells, regulates energy balance and fat stored.
Ghrelin– the hunger hormone. Regulates appetite, secreted when stomach is empty to let you know you are hungry.
Cortisol– the stress hormone. Released in response to stress and low blood glucose by raising blood pressure, blood sugar and modulating your immune system but leads to protein breakdown (muscle loss), fat storage, decreased thyroid and other hormonal imbalances when there are prolonged elevated levels.
Polypeptide YY– hormone that inhibits hunger.
Thyroid hormone– T3 and T4, regulated by thyroid stimulating hormone (TSH). Increases metabolism, blood pressure, regulates tissue growth.
Other Helpful Terms:
Gluconeogenesis – generation of glucose from non-carbohydrate sources like protein, aids in the metabolism of fat, protein and carbohydrates.
Fatty acid oxidation- fat burning
Catabolic– breakdown molecules and tissues
Anabolic- synthesis (make) of molecules and tissues