Part 1- Carbohydrates
Carbohydrates – What are they?
Carbohydrates (also referred to as ‘Carbs’) are one of the four main energy sources that fuel our bodies. These energy sources are called macronutrients, they come from food that’s digested in our stomach and converted into energy. The energy is then used by the cells in our muscles, organs and bones.
There are 3 other macronutrients in the human diet: protein, fats and alcohol. Each one delivers a different amount of energy (or kcal/calories) to the body:
• Fats 9 kcal of energy produced per gram.
• Alcohol 7 kcal,
• Carbohydrate 4 kcal
• Protein 3.8 kcal
We can think of macronutrients purely in terms of energy, however each has a different role, essential for the normal functioning of the body. Here, we are going to look at carbohydrates.
More About Carbs…
It is recommended that total carbohydrate should contribute around 50% of our daily food intake. They are very important for: providing energy to cells, muscles and organs; stopping the breakdown of protein and muscles; source of fibre; providing vitamins and minerals to the body. Carbs are broken down into glucose by the hormone insulin, before it is transported to the different areas of the body to either replenish energy or be stored as fat.
You may have heard of the term ‘free sugars’. ‘Free sugars’ is the term used to describe sugars added to foods and those naturally occurring in foods such as honey and syrup, excluding lactose. ‘Free sugars’ should not contribute more than 5% of your total daily energy.
Dietary fibre should also be considered as part of carbohydrate intake; Fibre is defined as carbohydrates that are not digested or absorbed by the body. Fibre has shown positive effects on blood lipid levels and gut health. The recommended amount of fibre for adults is 30 g/day. A good source of fibre is in your vegetables… make sure you eat a variety to get the most benefits.
As a population, we currently eat over the recommended amount of free sugars and below the recommended amount of fibre, contributing to the rising obesity levels in the UK.
Friend or Foe?
If your aim is to lose weight, carbs can be your friend if consumed correctly; your enemy if you eat too much. Remember, it’s important to carry on eating carbs when trying to lose weight, regardless of what some people advise. There are studies suggesting carbs may harm your health or prevent you from losing weight, this is not necessarily true. As shown above, the term ‘carbs’ includes sugars and fibre, therefore the key is what type of carbs are you eating.
Low GI and High GI
You may have heard the term low GI or high GI before, but what does GI mean?
GI is the abbreviation for glycaemic index, which refers to the speed that carbohydrates are broken down into glucose. Low GI foods are more preferable, they are more stable and provide a steady flow of energy to the body.
Examples of Low GI foods:
Oats, berries, broccoli, chickpeas, beans, spinach, asparagus are all low-moderate GI carbohydrate sources.
Vegetables, especially dark leafy greens, are great sources of carbohydrate as they can ‘bulk up’ meals, are low in calories and contain lots of vitamins and fibre.
Other foods, such as a small sweet potato or spoonful of brown rice, are more filling and are perfect for providing energy after a workout. However, as they are moderate-high GI, they should be consumed in small amounts.
Examples of High GI foods:
Chocolate bars, rice, cereals, muesli, some fruits and fruit juices are all high GI foods.
The problem with High GI foods is – the more you have, the more you want. Large portion sizes mean higher calorie intake and bigger increases in blood sugar; this is what leads to weight gain. Foods with a higher GI have been associated with an increased risk of type 2 diabetes.
An easy way to figure out if food is higher GI… If it tastes very sweet, chances are it probably contains more sugar and has a higher GI. So, continue to eat carbs, but remember to check the portion size and opt for low GI choices.
How to eat carbs and still lose weight?
1. Consume carbs in moderation
2. Choose low GI foods
3. Eat to fuel your day not to fuel your sleep
4. Go for dark leafy greens- packed full of fibre and vitamins
What to avoid?
Carbs can become a problem when they are consumed in large amounts, and can lead to the development of diseases such as type 2 diabetes, cardiovascular disease and contribute to gastrointestinal issues. The problem with consuming large amounts of carbs is that your body doesn’t require all of the extra energy, unfortunately this extra energy is stored in the form of fat.
Why does this occur?
Carbohydrates are broken down into small molecules called monosaccharides in the stomach and are absorbed into the blood in the small intestine. The pancreas to bring blood sugar levels down releases the hormone insulin. The primary role of insulin is to reduce blood sugar levels; blood sugar has huge effects on brain function so the body attempts to keep this constant. Insulin turns blood sugar into energy (glucose) for use by the liver and muscles. In the liver/muscle, glucose is turned into glycogen, the fuel used by the muscles during exercise. Fat cells are also able to absorb glucose from the blood stream.
Insulin resistance and type 2 diabetes
When there is a high amount of carbohydrate consumed on a regular basis, the liver, muscles and fat cells may stop responding to insulin. This means that the circulating blood sugar levels remain high. This causes an even higher amount of insulin to be released to help the glucose move from the blood and into the cells.
Eventually the pancreas struggle to keep up with the demand for more insulin, and they can fail to produce enough insulin needed to bring down the glucose levels in the blood. This is known as insulin resistance and can lead to the development and progression of type 2 diabetes. Some studies have shown that the incidence of type 2 diabetes can be reduced through dietary management alone, without the use of painkillers such as Metformin.
Pre and Post exercise advice
Having a meal with a source of carbohydrate around 2-3 hours before you exercise will help to give your body some extra energy, and also keep your brain functioning fully throughout.
Carbohydrates are extremely important after exercise. During a swimming lesson or other form of exercise, your muscles will use their glycogen for energy. Muscle glycogen needs to be replenished through the consumption of carbohydrates so the muscles can recover after exercise.
If carbohydrates are consumed within 2 hours of exercise, glycogen stores can be replenished quickly, ready for the next training session. If carbohydrates are not consumed within 2 hours, it can take much longer to replenish these muscle glycogen levels. Just think of all of the extra swimming practice you can fit in if you replenish your body after your swim!
To lose weight you should continue to eat carbohydrates, but ensure these are from low GI sources such as vegetables, beans and pulses. Carbohydrate consumption is essential after exercise to ensure that you are refuelling your muscles. This allows for recovery, prevents fatigue and prepares you for the next trip to the pool or in the gym.
On a final note, everybody is different, there’s lots of confilcting advice around nutrition for weight loss. The carbohydrate needs of a professional rugby player are very different to those of someone trying to lose weight, always tailor advice to your own individual needs. Any change to your diet should be discussed with a doctor or nutritionist before undertaking.
If you are interested in the effects of carbohydrates on the body, the book ‘The 8-Week blood sugar diet- Michael Mosley’ is a great read.
Contact me for more advice and a tailored plan – firstname.lastname@example.org