When we need them, sources, amounts and timings.
The following article outlines some key information on dietary carbohydrates, such as our needs for them, what happens if we have too much, ideal sources, and how to work out the amount you need in your diet in relation to your health and fitness goals. By the end of the article, we want you know how to provide the right amount of carbs in your diet to fuel muscle for intense exercise, aid recovery, provide optimal stable energy levels throughout the day, without increasing body fat.
Carbohydrates come in a variety of forms such as, starchy carbohydrates, vegetables, fruits, pulses, and nuts. This article is mainly concerned with the starchy carbohydrates. So, when referring to carbohydrates in this article we are referring to starchy carbohydrates such as potatoes, rice, pasta, bread, cereals, porridge, crackers, and biscuits.
What happens when we eat carbohydrates and sugars?
When we eat carbohydrates our digestive system breaks them into glucose molecules, and release them into the blood stream, the pancreas releases the hormone insulin in response to raised blood glucose levels, insulin binds to muscle and liver cells, which creates a cascade effect that causes glucose to enter muscle and liver cells, where they are then stored in the form of glycogen. These glycogen molecules can be used later to produce the energy we need to drive cells called “ATP”.
The average adult can store about 500-grams of glycogen in their muscles, and 100-grams in their liver, that’s about 2000-kcal and 400-kcal of glycogen respectively. The glycogen stored in muscles will be used as energy for that specific muscle and will not leave it. The liver can release glucose back into the blood stream if glucose blood levels drop. It would take about 90 minutes of strenuous activity of 75% maximal effort to us up your glycogen stores in muscles and liver.
Why we need carbohydrates.
Carbohydrates are the predominant source of energy for muscles at effort levels of about 75% and above, this is why I’ll often refer to carbohydrates as “rocket-fuel” to clients because it powers higher intensity muscular contractions. They’re essential for optimal performance in sports that require bursts of high intensity like football, rugby, and tennis, or running fast. Athletes will aim to replenish glucose stores in muscles after training hard to aid recovery. Carbohydrates will also bulk muscle up after a hard weight training session, this is due to the fact they need draw up to three times more water than their constituent parts when stored in muscle.
Carbohydrates are not the main source of fuel for muscles at lower intensity exercise like walking, light jogging, and light cycling or any activity below 70% effort level. These intensities are predominantly fuelled by dietary fats or fat reserves in the body. The fitter an individual is the greater their ability to use fat as an anergy source at higher muscular work output.
Too much starchy carbohydrates & sugar
The evidence is crystal clear, over consumption of processed carbohydrates and refined sugars are one of the main contributing factors metabolic disorders in the west. A metabolic disorder is a condition that disrupts the process of converting food into energy and getting rid of waste. Insulin resistance and type two diabetes are the main metabolic health conditions associated with multiple of chronic health problems that effect longevity and quality of life. If we consistently flood the bloodstream with more glucose from carbohydrates than we can process, over time we will increase the risk of becoming insulin resistant or developing type two diabetes.
Insulin resistance and type 2 diabetes occur when the body doesn't use insulin properly. As we mentioned earlier insulin is a hormone that helps your body's cells use glucose for energy. When cells start to become resistant to the effects of insulin, glucose builds up in the blood stream. A build up of glucose in the bloodstream can damage the lining of blood vessels leading to health problems, such as arteriosclerosis, heart disease, and strokes. If insulin resistance persists and reaches a critical threshold they will be diagnosed with type tow diabetes. In the UK this is s fasting blood sugar level of 11mmol/L or a HbA1c level of 48 mmol/mol.
Insulin resistance can also have negative consequences for muscle mass and body fat. If a person is insulin resistant, glucose cannot be shuttled effectively into muscles, resulting in muscle becoming starved of energy and a muscle that is starved of energy will get smaller which is termed “muscular atrophy”, thus reducing its capacity to draw glucose out of blood even more. The risk of increasing fat stores increases if the muscle cannot take up glucose. The body increases fat stores when muscle cannot take up glucose by diverting glucose to the liver to the liver, which convert it into fatty acids, which then packages those into triglycerides, and to be transported to be stored in body fat by lipo-proteins. If this process keeps occurring over time it will significantly increase body fat stores.
Testing for blood glucose levels and type two diabetes
If you’re interested in checking your blood glucose levels, there are two methods I recommend to clients. One involves a doctor and the other you can do yourself for about £50.
The HbA1c Test
The HbA1c test is a blood test that measures the average level of glucose in your blood over the past 2-3 months. The HbA1c test works by testing the haemoglobin protein. Haemoglobin is a protein found in red blood cells and carries oxygen from your lungs to the rest of your body. As glucose levels rise in your blood, some of the glucose attaches to haemoglobin, forming a glycated haemoglobin molecule. The HbA1c test looks at how much damage glucose has done to the haemoglobin protein molecules, and this is used to calculate your score. You can get this done at your GP or privately. The great thing about this test is that it’s a look at your glucose levels over 2-3 months, and not a snapshot of one moment in time.
Continuous glucose monitor
This test can be done privately, you buy a sensor online, attach it to your arm, link to an app on your phone, and it sends glucose blood levels every 15 seconds to your app for 2 weeks. I’ve used the monitor myself and found it very user friendly. The great thing about using a glucose monitor is that it shows how your blood sugar levels react to certain foods, letting you see what carbs agree with you and which don’t. I found that a burger and chips sent my blood glucose levels surging from my normal level of 5.0mmol to 10mmol then dropping drastically to 3.5mmol, causing me to feel very sleepy. While a breakfast of eggs, potatoes and salad only raised my blood glucose levels to 6.5mmol and over the next few hours slowly returned to 5mmol.
A general rule of thumb when choosing yours type of carbohydrates are the less processed the better. Through tracking my blood glucose levels my preferred starchy carbohydrates are potatoes followed by rice as these are the least processed, and more slowly absorbed into the blood stream causing less of a spike.
Generally, try to keep wheat products like pasta and bread to a minimum as they’re more processed, low in nutrients, spike the blood glucose levels rapidly, increase feelings of fatigue and lethargy, while increasing sugar cravings in the coming hours. Wheat based food are fine occasionally for pleasure or as a treat, they also make a convenient source of energy for a hike or long bike ride. When eating bread, try and eat sourdough as the bacteria in the starter culture improve the nutrient content while reducing substances like phytic acid that reduce nutrient absorption. When eating pasta try and make sure it’s a moderate portion of the plate and includes significant vegetables.
For the same reason as above, we also don’t recommend eating cereals, porridge, crackers and biscuits as they have the same effect on blood sugars and in some cases even worse as they tend to be eaten alone without any plant fibre which causes even greater spikes in blood glucose levels. The more processed carbohydrates are the quicker they’ll spike your blood sugar levels, so try minimally processed carbohydrates to achieve balanced blood sugar levels.
It goes without saying refined sugars should be limited to as little as possible as these spike the blood sugar levels the most, but if you do have something sweet put it at the end of a meal rather than as a standalone snack as this will lessen the spike blood glucose.
Examples of different kinds of starchy carbohydrates carb content
100-grams of butternut squash = 15 grams of carbohydrates
100-grams of purple potatoes= 15 grams of carbohydrates
100-grams of sweet potatoes = 15 grams of carbohydrates
100-grams of baby potatoes with skin = 15 grams of carbohydrates
100-grams of baked potatoes with skin = 21 grams of carbohydrates
100-grams of roasted potatoes with skin = 28 grams of carbohydrates
100-grams of mashed potatoes with skin = 33 grams of carbohydrates
100-grams of cooked rice = 28-grams of carbohydrates
100-grams of pasta = 25-grams of carbohydrates
100-grams of porridge = 11-grams of carbohydrates
100-grams of sourdough bread = 52-grams of carbohydrates
100 grams of wholegrain bread = 41-grams of carbohydrates
100-grams of muesli = 57-grams of carbohydrates
100-grams of crackers = 61 grams of carbohydrates
The amounts of carbohydrates you have in your diet is dependant on your goals, activity levels, and body weight. Its very difficult to give a precise amount that’s right for everyone in this article as context and nuance is critical in making that decision, below are some rough outlines on some possible different carb consumptions on a daily basis for different goals.
One thing to note is its unlikely anyone would be able to be able to absorb more than 60 grams of carbs effectively in one meal, so the following should be spread over several meals. Below are some averages for different types of goals.
0.5- 3 grams of carbohydrates per kilogram of body a day Active people not wishing to lose body fat.
Those who exercise up to 60 minutes:2-4 grams of carbohydrates per kilogram of body weight per day.
Those who exercise 60-90 minutes: 4-6 grams of carbohydrates per kilogram of body weight per day.
Those who exercise over 90 minutes: 5-7 grams of carbohydrates per kilogram of body weight per day.
Tips for avoiding spikes blood glucose levels.
Reducing the spike of our blood glucose spike will, reduce inflammation, reduce metabolic disorder, reduce fat gain, improve muscular health and energy levels. We’ve outlined the best sources and amounts of carbohydrates, but its also how you eat them that will also dictate how they release into you blood.
1. Don’t snack. By avoiding snacking and you’ll allow give our blood glucose levels time to normalise and produce less insulin.
2. Always include veg in meals. By including vegetables contain fibre, and fibre has been shown to slow down the release of glucose into the blood stream.
3. Add vinegar to carbohydrates. Vinegar contains acetic acid which like binds with glucose to slow down the release of glucose into the blood stream. It can be apple cider vinegar, balmsamic vinegar, and rice wine vinger, add a tablke spoon to your carbs.
4. Add little healthy fat. When natural fats are added to carbohydrates, they also slow down the release of glucose int the blood.
5. Sugar at the end of a meal. If you really want to a something sweet containing sugar have it after a meal not by itself, as the food from your main meal in your stomach will slow down the release of the sugars.
6. Move around after a meal. You can get glucose into your muscles without producing any insulin by moving around after meals. Glucose can enter muscles without insulin through a process called muscle contraction-induced glucose transport. This process is independent of insulin and is activated by muscle fibres contracting. When muscles contract, they release calcium ions, which in turn activate glucose transporter 4 (GLUT4) to move from inside the muscle cell to the cell membrane. GLUT4 then allows glucose to enter the muscle cell.
In recent years carbohydrates have been demonised when it comes to poor health and weight gain, but a usual it’s all about balance, too much and you risk developing metabolic problems too little and your muscular performance drops. So here is the take away, try and eat minimally processed carbs, with vegetables and proteins for a complete meal. If you can add a little fat and vinegar, it will slow the release of glucose right down reducing your risk to metabolic diseases like type two diabetes and all the health issues that come with it. Remember the more you exercise the greater your needs, and the more you want to lose body fat the less of it you need to eat.