Food, Nutrients, Macros & Micros
Aim of Article: explain the basics of nutrients
Obviously food is a pretty important part of any diet (i’ll give you a second to pick your jaw off the floor…), as it is the vessel through which we consume nutrients, defined as substances that provide nourishment essential for the maintenance of life and growth.
Understanding the importance of nutrients and the basics of micro/macro and essential/nonessential nutrients is the cornerstone of any decent diet strategy.
First up all nutrients can be split into two categories depending on the quantity in which they are required Macronutrients (> grams) and Micronutrients (typically < 100 milligrams). While essential and nonessential simply relates the whether we can produce the nutrient (nonessential) or not (essential) from other nutrients.
There are 6 macronutrients, which can be subdivided into those that produce energy/calories (protein, fats, carbohydrates and alcohol) and those that don’t (water and fibre).
Micronutrients are split into two categories, those coming from organic compounds (vitamins) and those from inorganic elements (minerals)
Holdup, what is a calorie?
A calorie (kcal) is simply a unit of energy, defined as the energy required to raise the temperature of 1 g of water 1 degree celsius. Think of calories as the energy in food we need to fuel all our vital processes, from walking and breathing to thinking and maintaining an immune system.
Energy-providing macronutrients – There are only 4 nutrient groups that we can utilise for calories (energy), Protein, Fats, Carbohydrates and Alcohol, of which have differing roles and calorie-densities (calories per gram).
Protein essential / 4 calories per gram
Critical for physiologic functions of body such as maintaining skeletal muscle, hormonal levels, organ function and immune system.
Proteins are made up of amino acids, which are the building blocks for proteins. The order in which they are arranged determine the structure and function of the protein. There are 20 amino acids, of which we can create 11, leaving 9 which are considered essential (and we must consume them as part of diet). Protein is broken down inside the body into these amino acids, and they can be rebuilt (like lego) and repurposed into the proteins we need.
Unlike carbohydrate and fat, there is no specific storage site in the body for protein, so if your body needs more than it’s getting from diet, it will help itself to protein from organs or muscle tissue.
Why is it so popular in diet strategies?
- Eating protein signals the body to build muscle through the muscle protein synthetic response
- It is highly satiating, meaning it helps you feel fuller for longer, and anything that makes the actual diet easier is a good thing
- Takes more energy than other macronutrients for the body to process, known as the thermic effect of food. Your body ends up burning off around 20% of the 4 calories/gram just processing the proteins into useable forms. Not a good point if you’re starving on a desert island, but good if you are looking to cut fat.
- As we know we need a certain amount of protein a day just to keep up normal bodily functions, if we are going work our butt off in the gym to convince our body to increase muscle mass, we better make sure we have excess protein to build it.
Fat essential / 9 calories per gram
Their high caloric density makes them a great energy source, but they are not just useful as energy stores; they are vital for maintaining healthy cells, the hormonal system and utilisation of fat soluble nutrients.
Dietary fat consist of triglycerides and cholesterol. Triglycerides can be subdivided further into saturated, polyunsaturated, monounsaturated and trans fats. All of which have different impacts and roles in the body, but we’ll save that for another time.
For now it is just important to note:
- Saturated, polyunsaturated and monounsaturated fats have all been proven to be useful for various bodily functions. Trans fats on the other hand can jog on. They are beyond useless and will do more harm than good. Avoid.
- We can synthesise most of the fats we need from diet but there are two essential fatty acids we cannot and must consume from the diet, alpha-linolenic (an omega-3 fatty acid) and linoleic acid (an omega 6 fatty acid).
Carbohydrate nonessential, but useful / 4 calories per gram
Known as carbohydrates due to their composition of carbon, hydrogen and oxygen, we use these substances as a glucose-based energy source. There are three types,
- simple-carbohydrates (sugars),
- complex-carbohydrates (starch)
- complex-non-digestible-carbohydrates (fibre).
We use simple and complex carbohydrates as a source of glucose, either directly from sugars or by breaking the complex-carbohydrates down into glucose, before absorbing them into the bloodstream. From here glucose then enters the cells with the help of insulin.
The speed at which glucose is released into the blood depends on the type of carbohydrates (simple carbs are absorbed faster than more complex-carbs) and is known as the glycemic index (GI). The higher the GI value, the faster they are absorbed.
Unused glucose can be converted to glycogen and stored in the liver and muscles. If more glucose is consumed than can be stored as glycogen, then it is converted into fat for long-term storage.
As we are able to utilise alternative sources of energy in the absence of carbohydrates, such as fat (ketogenesis) or protein (amino-acid catabolism), carbohydrates are technically not an essential nutrient.
However they are not harmful or useless; carbohydrates can be a great tool once applied correctly depending on your goals. Obviously if your aim is fat loss, eating copious amounts of carbohydrates is going to hinder fat loss. Conversely if you are after more muscle, starving yourself of carbs could result in your body reaching for proteins as it’s alternative energy source.
Also, avoiding carbs completely makes a nutrient-rich-diet harder, as fruit/vegetables are a great source of the micro-nutrients.
Take home message is that carbs or not essential, and although as with everything they can be harmful if abused, applied correctly they can be a great asset to some diet strategies.
Alcohol nonessential, not-useful (health-wise at least) / 7 calories per gram
Although we can derive energy from alcohol, it is far from essential, and unlike carbohydrates, has limited use in diet strategies. Whereas carbohydrates can be justified by their nutrient dense sources, and as an optimal alternative energy source compared to fats or protein; alcohol often comes as empty-calories (no additional nutrients) and has negative side effects that directly hinder performance.
However as alcohol has purposes outside of optimal nutrition, you may choose to incorporate it into diet to relax or socialise. Of course we are not going to give it the green light, but if factoring into a diet, they behave similar to fats and carbohydrates, with roughly 7 calories per gram of alcohol. So as long as it’s not abused, it is possible to include it and still make progress. Better yet if it comes from sources that at least have some nutrients such as red wine.
When you first ingest alcohol, your body makes metabolising it a top priority, as there is no storage site for alcohol in the body.
Issues of alcohol for training
- Easy to drink lots of calories
- Often nutrient low sources (empty calories)
- Impaired performance
- Impaired recovery
- Strip / prevent body from digesting certain nutrients
Non-energy-providing macronutrients – The other two macronutrients do not provide energy (kcal), but are still considered essential
Arguably the most important nutrient, it is essential for all life on earth; you can go weeks without food but only days without water. We are between 50-75% water, of which forms the basis of all our anatomy, bodily functions and performance.
The list of benefits from water is huge, from maintaining cell structure and transporting nutrients, to regulating temperature and eliminating byproducts and toxins from the body.
Just 2-3% decrease in optimal hydration will cause a significant reduction in strength and speed, while a decrease > 7% could shut you down for good.
As we have no storage for water, we require fresh supplies every day. The amount required varies person to person, based on size, metabolism, weather, diet activity levels etc. As a very rough figure, most adults require around 2-3 litres of water per day.
Although we cannot absorb fibre, and it contains no nutrients, it is still deemed an essential nutrient due to its importance in the digestive process. We require fibre to process our other digestible foods and nutrients.
Again requirements vary person to person but are typically around 25-40g per day
Unlike macronutrients, these are required in minute quantities and do not provide energy, but are still vital for optimal functioning of the body. Their function is to enable the many essential chemical reactions to occur in the body.
There are two types of micronutrients, vitamins (organic) and minerals (inorganic):
Vitamins – Organic molecules (made by plants or animals) and can be broken down by heat, air acid etc. They are predominantly co-enzymes and are essential for normal metabolism, growth, development and regulation of cell function.
Vitamins are either fat-soluble and stored in fatty tissue when in excess (Vitamins A, D, E and K) or water-soluble and excreted in urine when in excess (Vitamins B and C), thus needed daily.
Minerals – Inorganic elements that are more resilient to damage from heat, air etc compared to vitamins. They are predominantly co-factors (inorganic ions required by enzymes for activation). Other minerals are systemic electrolytes and are essential in co-regulating ATP (molecule we use for fueling our muscles).