Your Metabolism: 101

Your metabolism is the rate at which your body uses or burns calories. 
However, metabolism isn't just a weight-loss buzzword; it's actually a term that is used to describe all chemical reactions involved in maintaining life.  

Nutrition is the key to metabolism. The pathways of metabolism rely upon nutrients from food that get broken down in order to produce energy.

Metabolism can be conveniently divided into two categories:

1. Catabolism - complex materials in the body are broken down to simple.  It is a destructive process involved in the release of energy.  This is a normal body process and involves the clearing of wastes, toxins from the body.

2. Anabolism -is involved in the constructive processes of the body.  Simple components (the amino acids from proteins) build the body’s complex structures and new materials including our hair, teeth, and bones.
(You can read much more about this in my article, Homeostasis & Dietary Direction: Where are YOU Headed?)

So, how can metabolism be enhanced to regulate weight?  Below I explain the 3 components of metabolism, what influences metabolism, and how macro-nutrient distribution pays a part:

Metabolism is made up of 3 components:

1.  The basal metabolic rate (BMR).  
This is the energy your body expends to sustain life and includes the basic involuntary functions such as breathing, beating of the heart, kidney filtration, temperature regulation, and muscle tone.

• Approximately 70% of total calorie intake is used for BMR.

2.  The thermic effect of food (diet thermogenesis).  
This is the energy your body expends to digest, absorb, transport, metabolize, and store nutrients from the food you eat (see more below).  

• Approximately 10-15% of total calorie intake is spent on digestion.

3. Physical activity.  
This includes the energy used for your every-day muscle function and movement.  

• Approximately 15-20% of total calorie intake is used for muscle function.

​The Influences on BMR

In general, the calculations for BMR calories are:

• Women: body weight (lbs) X 10
• Men: body weight (lbs) X 11

However, your diet and lifestyle choices can influence your BMR greatly, which also influences weight regulation.  Your metabolism speeds up or slows down to adjust to these influences.  It is the mitochondria within the cells, which are its metabolic powerhouses, that are affected. 

The body also fights to maintain a certain “set point”, which is the genetically inherited body composition.  The set point is controlled by activation of a specialized fat called "brown fat".  Brown fat is thermogenic (burns heat) and is filled with iron-rich mitochondria that are metabolically active.  Only 1-2 % of the body is brown fat, which is bound to the skeleton near the neck, arteries, and internal organs.  (Yellow fat, on the other hand, contains very few mitochondria and acts as insulation for your body.) 

Some of the factors that influence BMR include:

• Age: BMR peaks in the mid-twenties, and then drops about 2% per decade.  


• Exercise: A higher activity level raises the BMR.  It also activates brown fat and lowers the body’s set point.


• Body composition:  The more muscle in the body, the more energy is used. Increasing muscle mass through exercise also raises BMR.  Fat tissue (yellow), however, is not metabolically active.


• Gender:  Males often have more muscle mass and therefore a higher BMR.


• Body size: The larger the person, the higher the BMR, because it takes more energy to complete an exercise or activity.  


• Calories consumed: When calories are reduced, metabolism slows down to adjust.  Metabolism speeds up to adjust to increased calories and maintain the set point.


• Dieting/food restriction: During weight loss and weight gain cycles, the BMR is lowered because the body thinks starvation is happening.  (Illnesses and medications can have similar effects.)


• Food quality: Poor nutritional value in food also signals the body to conserve energy and slows BMR.  Metabolically draining foods are the processed and refined foods that are void of nutritional value.  Metabolically enhancing foods are whole foods that are rich in vitamins and minerals.


• Trace mineral malnutrition:  Specific nutrients that most effect metabolism are chromium, zinc, iodine, potassium, magnesium, vitamin C, vitamin B, and vitamin E.  


• Toxin overload: Toxins inhibit normal mitochondrial function.


• Thyroid function, adrenal function (stress), and hormonal regulation: ​ Dysregulation in these causes brown fat to become less metabolically active.

​The Thermic Effect of Food

It is possible to take advantage of the thermic effect of food and strategically enhance your metabolism when trying to lose weight.

The thermic effect of carbohydrates is approx 10%.
The thermic effect of fats is approx 3%.
​
But, best of all...

The thermic effect of protein is up to 30%! 
This means 30% of the calories in the protein itself are burned to process the food. So, the body must work hardest to break protein down into amino acids.

So, to take advantage of the thermic effect of food, especially protein:
  

• Eat frequent thermic meals to burn fat and stoke metabolism (consisting of healthy protein, healthy carbs, and essential fats).
• Eat some healthy protein with every meal and snack.
• Goal: 20-30% of daily calories from protein (for weight-loss), which is approx 25 g of protein at each meal.

(Over 30% of calories is considered a high protein diet = unnecessary for most people unless you're a competitive body builder.)

Protein also prevents the body from catabolizing muscle tissue.  The more muscle you have, the better your BMR.  Muscle burns 2-4X more calories at rest (compared to yellow fat).  Protein boosts metabolism!  

Protein is also very satiating  and keeps you feeling full longer.  See HERE for a summary of a scientific study that concluded: "Protein plays a key role in body weight regulation through satiety related to diet-induced thermogenesis."
​​

The protein sources you choose matter!  See my Guide to Choosing Healthy Meats and Seafood for choosing the healthiest sources:

• The most healthy animal products are: Grass-fed, Organic, Antibiotic-free, and Hormone-free.
• The healthiest seafood are from: Clean, wild-caught, cold-water sources.
• The healthiest dairy products are: Raw, from grass-fed animals, whole (full-fat), and fermented.
• Most legumes, nuts and seeds eaten for protein should be soaked and sprouted to remove anti-nutrients (read more).

Protein from animal sources are acidic, so remember The Importance of Acid/Alkaline Balance! Drink plenty water and eat 8+ servings of alkalizing fruits and vegetables per day for pH balance.

References:

Bartholomy, P (2014).  Diet and Exercise. MHNE 609. Lecture conducted from Hawthorn University.

Bartron, L. (2005, December 13). Weighty Matters part 2. Hawthorn's Tuesday Teleconference Series. Lecture conducted from Hawthorn University.

Diet induced thermogenesis study: 
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC524030/

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