What’s in my food?

By Murtaza Ahmed MD

One of the key mistakes I see in so many diet plans and programs is telling people or clients what to eat without properly explaining why they should choose those foods.  After all we are all intelligent people capable of making our own decisions, so why is it suddenly ok to be dictated to on something as fundamental as what we eat.  Nutrition is not some secret complex science that needs to be deciphered for the public by those few in the know, but is instead an interesting, understandable subject that when explained gives the user the ability to make their own decisions.  Think about it, you want to know everything about the new car that you are looking to buy or the latest TV in the store, so why shouldn’t you be aware of everything that you put into your body?

Before starting any diet it is important to understand the fundamentals of what food is made up of.  If you tried to do a job in a field you had no idea about you would likely either fail or waste a lot of time trying to learn, and the same goes for dieting.

In general foods consist of macronutrients (things we need in large amounts), micronutrients (things we need in small amounts) and indigestible substances such as fiber.  Macronutrients could be described as fuel and building blocks and consist of carbohydrate, fat and protein.  These are often misunderstood, for example some people feel that ‘carbs’ are bad and will make you gain weight, or fat will make you fat, but in reality they are all essential and each have very important roles to play in the body.  Micronutrients are all the vitamins and minerals such as iron, calcium, vitamin C and so on.  These do not provide energy or contribute directly to weight but are instead important in maintaining good health.  Eating a balanced diet consisting of ALL of the macro and micronutrients is very important and should form the basis of any diet.


Proteins are in made up of many smaller compounds called amino acids.   The proteins we eat are broken down into these amino acids in the gut and then used throughout the body to form different proteins.  Protein is found in abundance in all kinds of meat (chicken, red meat, fish), eggs, dairy products, and in lesser amounts in foods such as seeds, nuts, beans, lentils, and soy products.  Foods such as meat provide all of the amino acids we require whereas vegetarians need to have a variety of different protein sources if they are to obtain all these.  As well as being a building material, protein can also provide the body with energy and this is utilized particularly in starvation.  The body can break down its own protein when it has no other supplies coming in.  This is very important to consider in crash dieting as some of the weight you see yourself losing on the scales will be precious muscle and lean tissue that the body has broken down because it is ‘starving’.

The body is very good at recycling protein and as a result we only need a small amount each day to keep our supplies topped up.  The recommendations vary tremendously but anything over approximately 50g/day is probably more than sufficient for the average individual.  Contrary to popular belief even individuals partaking in exercise don’t really need any extra protein as the recycling mechanism actually becomes even more efficient!  Protein deficiency itself is rare in the western world and most people eat it in surplus, which unless is a very large amount is generally not harmful.

The main pitfall when it comes to eating protein is that in consuming it people inadvertently take in a large amount of carbohydrates and fats without realizing they are doing it.  Yes, meat has a large protein content but your average steak contains a lot of fat also, and milk is a good source of protein but is also full of sugar in the form of lactose.  Beans and lentils are marketed as high protein foods but also contain large amounts of carbohydrate.  This in itself is not a problem as long as you are aware of the additional macronutrients being consumed.


Carbohydrates are important in providing the body with energy.  The group can generally be broken down into ‘simple’ and ‘complex’.  Simple carbohydrates generally refer to sugars (of which there are many types) such as glucose or fructose.  Complex carbohydrates are formed by lots of simple ones joining together, of which starch is a good example.

Unlike proteins the main role of carbohydrates is to provide the body with energy.  Each one-gram of carbohydrate, simple or complex, provides the body with four calories.  The difference between sugars and starches is not how much energy they provide but how fast they provide it.  Sugars like glucose don’t need to be broken down and can be absorbed very quickly whereas starches need to be broken down into sugars in the gut before they can be absorbed.  We will discuss the implications of this in a future article.

What you need to understand for the moment is that carbohydrates have a vital role in providing the body with energy and without them we would struggle to survive.  In fact some organs in the body such as the brain can only get their energy from carbohydrates so it is important that they are provided.

Once absorbed into the body very little glucose is actually kept in the blood.  Most of it is stored in the liver and muscles as glycogen.  These stores can be rapidly turned back into sugars for energy when we need them.  Carbohydrates have been given a bad name by many diets that tell us that we should have as few ‘carbs’ as possible but these claims are actually based on very little evidence.  When eaten in the right forms and in the right amounts they are important to any healthy diet and should not be totally avoided.


Yes the dreaded fat!  I should start by saying that fat isn’t so bad.  We are made to think that all the fat we eat just goes straight to our bum, tum and thighs but on the contrary fat is an extremely important energy source and also forms part of every cell in the body, especially those that make up the brain and nervous system.

Fats can be found in many foods such as oils, butter, nuts and animal products.  There are many types of fat that you may have come across such as monounsaturated, polyunsaturated, trans fats, omegas, but for the moment I don’t want you to concern yourself too much with these.  The reason some are good and some are bad is mainly due to their effect on long-term health, but this is something we will discuss later.

The important thing to know is that fat is a very dense energy source, providing nine calories per gram (compared to four calories per gram of carbohydrate or protein).  This is one of the reasons people get into trouble when it comes to fat.  It is not that we shouldn’t eat it but more that we just need to be aware of how much we are eating.  Let me put it into context.  Fat is like a log in a fire, it will provide a steady amount of heat for a long time, but a little bit will go a long way.  Carbohydrate on the other hand is like kindling.  It is good for providing intense bursts of heat but would not be your long-term fuel choice.

So in order to be healthy when losing weight, all diets should consist of a good mix of carbohydrate, fat and protein.  Different diets recommend different proportions of each but this is not an exact science and nobody can actually say with any certainty what the ideal amount of each is.  It is safe to say however that no diet should consist primarily of one type of macronutrient, as then you would be deficient in the others, which would eventually lead to adverse effects.

Now you know the basic make up of all foods I can safely go on to discuss specific diets, foods and ideas knowing that you will understand the reasoning behind them and have a much higher chance of succeeding in your goals.

About Murtaza Ahmed MD

Dr Murtaza Ahmed is a General Practitioner sub-specializing in the field of Sports, Exercise and Nutritional Medicine. He graduated from The University of Nottingham, England, and in addition to his medical qualification he holds a Masters in Sports and Exercise Medicine (MSc), Bachelor of Medical Sciences (BMedSci) and Membership of the Royal College of Physicians (MRCP London).
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