An Intro to Nutrition and Metabolism

INTRO TO NUTRITION AND METABOLISM

By: Mark Robinson (Accredited Dietitian) ‘Health Man Mark’

Energy is the overriding term for weight: as in weight consumed daily through nutrition and weight expended daily through exercise and resting metabolism. Weight is measured in either kilojoules (kJ) or calories (Cal). However, these terms are not equal in value: 1 Cal is equivalent to 4.2 kJ.

Achieving an energy deficit means consuming less daily energy than expended energy. An individuals daily energy expenditure is dependent on a number of factors. These include age, gender, muscle and fat composition, daily nutrition patterns, genes, and of course exercise type, intensity and frequency.  

Resting metabolism is the term given to the speed at which we burn up energy/weight whilst not intentionally performing exercise. Thus, when in a resting state – energy is used to aid in essential living requirements of breathing, maintaining homoeostatic body temperature, cognitive function, and digestion. This resting metabolism is therefore positively related with younger age, lean muscle mass or fat free mass, small frequent meals and snacks high in protein and fibre.

Exercise then makes up the remaining contribution towards daily energy expenditure. Resistance and cardio training impact differently on energy usage, however both are necessary to achieve greater lean muscle mass, and eliminate fat mass. Resistance type training will aid in the development of muscle size and tone, whilst still burning energy. Cardio typically improves fitness levels and burns energy at differeing rates dependent on type and dintensity. Intensity plays an important role in the efficiency of energy expenditure – as at higher intensities one is able to utilise kilojoules from carbohydrates, fats and protein  for energy – which therefore expends a greater volume of overall energy.

The 3T Formula of mine uses common sense to appropriately plan your nutritional needs: The first T stands for the TOTAL amount of Energy to be consumed in a day (Cal or kj). The second T is for TYPE of Macronutrients and thus the recommended Macronutrient Ratio to best make up the daily energy consumption. The third T refers to nutrient TIMING.

In addition, Micronutrients are the vitamins and minerals essentially found in vegetables and fruits that provide us with optimal brain function, boosted immune systems, a healthier heart and balanced hormonal control.

The below describes a typical example of a days Energy Intake appropriately spread out across three main meals and three mid meal snacks. Note this is an example as again a personalised structure requires individual assessment as discussed above.

Thereafter, I describe the Macronutrients and their functions as well as Micronutrients and Fibre and Sodium to give a complete Nutrition Education Summary.

Energy / kJ / Cal
4.2 kJ = 1 Cal

Example Female Daily Energy Intake & Expenditure 6000 – 8000kJ

1400   700   1400     700   1200   600

Example Male Daily Energy Intake & Expenditure 8000 – 10000kJ

1800   1000     1800      1000     1600       800

Contribution to Daily Energy Intake, by four MACRONUTRIENTS:

1. Carbohydrate 1g = 16kJ

Function: Most efficient source of energy provision for muscles during exercise.

There are two common groups of carbohydrates; Simple and Complex carbohydrates.

Simple carbohydrates:

These carbs are typically higher in sugar (refined), and should in most cases be avoided:

soft drinks, juice, lollies,  sugary cereals, sweet sauces, sweet bakery goods, ice-cream, flavoured milks.

Complex Carbohydrates:

Carbs that are more natural and thus lower in sugar. Usually appropriate choices for BF and Lunch:

rolled oats, natural muesli, brown rice or pasta, w/m bread, starchy veg (sweet potato, potato, pumpkin, corn), and beans (lentils, chickpeas), & multigrain ryvita or rice cakes as midmeals.

• Protein 1g = 16kJ

Function: Muscle growth, tone, repair & recovery, as well as immune system strength.

Chicken breast, grilled fish, tinned tuna/salmon

lean red meat, eggs

Dairy, nuts, mixed beans

• High protein (low carb & fat) powder or bar – WPI: post training & midmeals for muscle development, tone, recovery, and weight loss aid.

• Branch Chain Amino Acids – muscle protein stores, muscle size & muscle energy.

• Glutamine – muscle repair/recovery, immune system

• Creatine – muscle power, overall weight

• Fat 1g = 37kJ

Saturated (the most harmful) fats accumulate in the walls of blood vessels, forming what's known as plaque. Overtime this build up of plaque narrows the diameter of blood vessels making it harder for blood to be pumped to cells and organs of the body. The likelihood of a blood clot therefore increases as blood vessels become more constricted through plaque build up.

These Saturated fats, which are therefore associated with plaque build up in blood vessels, high Cholesterol, and weight gain include:

Full cream dairy, creams, butter, cheese, untrimmed red meat, oils, nuts – and therefore chocolates, bakery goods, fried/battered foods, creamy/coconut sauces

Un-saturated fats termed as Poly or Mono Un-saturated aid in lowering Cholesterol, brain function, and hormone production & release:

Polyunsaturated fats are multiple molecules of unsaturated fats causing a long chain of unsaturated fats known as Omega 3 or 6 fats. A Monounsaturated fat is just one strand of unsaturated fat. The benefits of these unsaturated fats lies firstly within their ability to remove plaque build up within the blood vessel walls caused by saturated fats, and secondly to thin our blood so as to make blood flow to organs and cells easier, decreasing the blood pressure, and the risk of blood clotting.

Therefore, healthier fat sources include:

Fish Oils, walnuts, almonds, avo, seeds, grapeseed or sunflower oil.

• Alcohol 1g = 29kJ

Standard drink ~10g Alc, therefore 290kJ, plus kJ from added carbohydrate.

Wine: 300kJ/std serving glass

Vodca & lemonade:~700kJ

Beer: ~500kJ

Low Alc beer: ~250kJ

MICRONUTRIENTS:

Multi Vitamins & Minerals, and Anti-oxidants – energy provision, fight stress & tension, protect against cell damage, and disease prevention.

Omega Fish Oil – brain activity, joint pain or inflammation, and heart safety.

Specific Vitamins and Minerals: dependent on diet inadequacy or an individuals life circumstances:

Electrolytes (Na, Mg, K+) – prevention of cramping, improved performance, recovery - endurance athletes training or competing for periods over 90 minutes.

Fibre

• No contribution to daily kilojoule intake

• Maintenance of low blood sugar levels
• Increased resting energy expenditure (metabolism) through digestion
• Sustained energy levels
• Regular bowel movements
• Feeling of fullness/appetite suppressing

• Wholegrains (seeds, nuts), wholemeals, green vegetables, fruit skin, lentils
• Recommended daily Vegetable intake of 2-3 cups per day OR 5 cups of Salad.
• Aim to chose foods with >8g Fibre /100g

Sodium (Na) – influences fluid retention within the body, and excess amounts increase pressure on the heart by thickening blood and closing blood vessels.

Aim for <130mg/100g of any product, or <2000mg/day.

As a guide 1g of salt contains 380mg Na.