1. GETTING TO GRIPS WITH VISCERAL FAT

Not all body fat is 'bad', as we need it to insulate and cushion our organs. It is when we have it in excess that it starts to affect our health, especially if we start accumulating it in our abdomen around our organs. This type of fat is called visceral fat, and the aim of this chapter is for you to get a deeper understanding on why excess visceral fat can make you sick. Don't worry if you find this section a bit technical - you can always revisit it as your understanding grows.

TYPES OF FAT

ADIPOSE TISSUE

The primary function of body fat - or adipose tissue - is to store and release energy, and to serve as insulation and cushioning for organs. Adipose tissue consists of fat cells, known as adipocytes, along with other supporting cells and blood vessels. Adipocytes produce adipokines, which are hormones and cytokines. The precise definitions of whether something is classified as a hormone or a cytokine is subtle and not important in the context of this book; just know that they are both types of chemical messengers.

There are two main types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is the predominant type and is responsible for storing excess energy as triglycerides (more about these here). WAT is found throughout the body, primarily under the skin (subcutaneous fat) and around the organs (visceral fat).

On the other hand, BAT is more abundant in infants and is involved in generating heat to maintain body temperature. Brown adipocytes contain a higher number of mitochondria (the little powerhouses that are in our cells, generating energy), which give them their characteristic brown colour. When activated, brown adipose tissue can 'burn' the stored fat and release heat, contributing to energy expenditure and thermoregulation (body temperature).

It is important to know that adipose (fat) tissue is not only used for energy storage and cushioning for our organs, but can also act in a way similar to an endocrine organ because of the hormones and cytokines it produces. In basic terms, these are messengers that, upon arrival to the target cells, tell the cell what to do. The body is constantly monitoring hormone levels, as we should not have too much or too little of any of them, but rather maintain a balance (called homeostasis). When something goes wrong in the body, this homeostasis is under threat, and adipose tissue plays its part in either keeping things in check - or causing havoc.

SUBCUTANEOUS FAT AND VISCERAL FAT

It is important to distinguish between subcutaneous fat and visceral fat.

• Subcutaneous fat helps to regulate our body temperature. It also provides us with protection, as it cushions our organs, bones and muscles. In addition, it serves as energy storage. We have subcutaneous fat all around our bodies. It is located directly under the skin, and you can typically pinch it.

• Visceral fat is also needed to protect our organs, such as the liver and pancreas. It helps with insulating them from the cold, and it can also act as an energy reserve; therefore, we do need some of it. It is when there is an excess level of visceral fat that problems can arise, as it can surround the organs, almost suffocating them.

The difference between the roles that subcutaneous fat versus visceral fat have in wellness and illness has been studied extensively. While they both form an extensive endocrine organ together, it appears that visceral fat produces more pro-inflammatory factors that cause low-grade inflammation throughout the body. This low-grade inflammation plays a key role in disease development (see here).

WHY WE STORE FAT

Energy is needed throughout our bodies for every single action or reaction. Our bodies have a sort of energy currency that we use in order for our bodies to function. This currency is called adenosine triphosphate, or ATP. We don't have an endless supply of it, and our bodies are designed to prioritise using ATP for vital bodily functions. Stored body fat is the hardest source of energy for our bodies to use. This is because we use more ATP to convert body fat into fuel than we do to make this conversion from the foods we eat.

You could simplify this by thinking of spending or saving energy the same way you do about spending or saving money. We are often careful about spending money, trying to save wherever we can, spending less rather than more. As simple as it may sound, our bodies have evolved to save rather than spend. In order to lose fat, including visceral fat, we need to try switching this saving to spending. So basically, you need to take in less energy (by eating fewer calories than you need) so that the body uses its saved energy.

SIMPLE AND COMPLEX CARBOHYDRATES

The most common source of energy in our diets comes from carbohydrates in the form of its breakdown product, glucose. The body prefers to use glucose as its main fuel source, as it is readily available. This is probably why we all love carbohydrates so much - we are almost designed to crave them because we get energy from them.

There are two groups of carbohydrates that give us glucose. There are simple carbohydrates, which taste sweet, such as your regular table sugar or honey. You would probably instinctively know that consuming these is not going to help you to lose weight. There are also complex carbohydrates, such as those found in potatoes and porridge oats. They don't taste sweet, making them seem innocent enough to include in your weight-loss diet.

While the sugar content in some foods, like oats, is not a concern, we need to understand that all carbohydrates will still break down to what are known as simple sugars - primarily glucose. And if we get enough of this glucose to fuel us, we don't need to start breaking down our stored energy reserves.

While the food pyramid currently endorsed by the Department of Health has now shifted so that the primary sources of starchy carbohydrates (bread, cereals, potatoes, rice and pasta) are on the second shelf from the bottom instead of being on bottom shelf, I still can't agree with the general recommended portions. The current recommendation for carbohydrates is 3-5 servings a day, with up to 7 servings for teenage boys and men between the ages of 19 and 50. Suggested serving guidelines are 1 cup of cooked pasta or rice (containing approximately 40g of carbohydrates), ? cup dry oats (also containing approximately 40g of carbohydrates) or 2 thin slices of bread (which very much depends on how this portion is interpreted, but would contain typically at least 20g of carbohydrates). Not only would the calories from these portions be, in most cases, already way too excessive, the reality is that most people, adults and children alike, are eating too many carbohydrates, which can promote weight gain and make it impossible to lose weight.

INTRINSIC AND EXTRINSIC SUGARS

Another basic thing to understand is the concept of the extrinsic sugars (otherwise also referred to as the added sugars) and intrinsic sugars. Intrinsic sugars refer to any sugars that are a part of the food itself and not something that has been added at any stage of processing, manufacturing or cooking. They are a natural part of grains, fruits and vegetables. Extrinsic sugars are the very opposite: they have been added to the food somewhere along the way.

The pyramid shows the following from the bottom to the top: 1. Eight glasses of water, a glass of hot beverage and a glass of herbal tea. 2. A variety of vegetables including turnips, cabbage, tomato, radish, onion, broccoli, cauliflower, butternut squash and carrots. 3. Fish, mussels, tuna, sunny side up egg, natural yoghurt, a glass of milk, chicken, beef and butter. 4. Avocado, walnut, pistachios, almond, nut butter, coconut oil, butter and olives. 5. Rice, bread, pasta and noodles. 6. Different types of fruits including orange, pear, grapes, watermelon, cherry, pineapple, banana, grapes and strawberry. 6. Ice cream, wine, popcorn, cake, soft drinks, coffee.

A good example of a product that has both intrinsic sugars and extrinsic sugars is granola. Typically, the base of granola is made of ingredients with only intrinsic sugars - such as oats, nuts and seeds. But then, to make it into granola as we know it, these ingredients are then mixed with extrinsic sugars - such as molasses or brown sugar - which are added sugars.

Your breakfast porridge oats contain just the natural intrinsic sugar. While oats have less than 1g of intrinsic sugar per 100g, they are still very high in carbohydrates, with about 65g in a 100g portion. Granola, on the other hand, might have only 50g of carbohydrates, but might have sugars in excess of 20g per 100g. For us - the consumers - the tricky bit is that we don't actually know what amount of this sugar is intrinsic sugar and what amount is extrinsic sugar.

GLYCOGEN AND FAT STORAGE

Glycogen is basically several glucose molecules bundled together. These bundles can be broken down into individual glucose molecules when needed. This can happen, for example, when we are fasting between meals, during exercise, or at any time when the glucose supplied by what we have just eaten is not sufficient.

If we are moving a lot, we are likely to use up the glucose we get from food to meet our energy requirements. However, any excess glucose that we don't use is...