Low-carb mania has resulted mainly from social media and fad-diet articles but are low-carb diets really necessary for fat loss? Let’s take a look…
WHAT ARE CARBS?
Carbohydrates (carbs) are one of the four macronutrients that provide calories, or energy, to fuel the body. They are comprised of sugar molecules that are bonded together and are broken down into glucose (sugar) before being absorbed into the bloodstream. One gram of carbs provides 4 calories. There are three main types of carbohydrate in food:
- Starches (complex carbohydrates): these are made up of many sugar units bonded together, and are found in foods that come from plants. It includes starchy foods, such as bread, rice, potatoes and pasta, which provide a slow and steady release of energy throughout the day.
- Sugar (simple carbohydrates): is found naturally in some foods, including fruit, honey, fruit juices, milk (lactose) and vegetables. Other forms of sugar (for example refined sugar) can be added to food and drink such as sweets, chocolates, biscuits and soft drinks during processing, or added when cooking at home. These provide a quick release of energy.
- Fibre: is only found in foods that come from plants. Fibre helps keep our bowels healthy and some types of fibre may help lower cholesterol. Good sources of fibre include vegetables with skins on, wholegrain bread and pasta and beans and lentils.
WHAT DO CARBS DO?
Carbs are the body’s primary fuel source. They allow our heart, lungs, kidneys, brain and muscles to function properly. Carbs are particularly important to fuel the brain, helping us to think clearly and to balance our mood, as well as to enable our muscles to work effectively during exercise. They also prevent protein from being used as an energy source and enable fat metabolism.
SO WHY ARE WE TOLD TO AVOID THEM?
The reasons to restrict carbohydrates are based around the function of insulin. Insulin is a hormone which is secreted by the pancreas and its main function is to lower blood sugar levels by moving the glucose to the various parts of the body and aiding its absorption. Excess glucose is be stored in the liver or in fat around the body, which is why it is commonly referred to as “the storage hormone”. It’s thought that releasing too much insulin in the body from carbohydrate intake causes weight gain because if the energy isn’t used, it is stored as fat.
WHAT THE SCIENCE SAYS
Fat loss is determined by your energy balance. If you consume less calories (or energy) than you burn, then you will lose weight. If you consume more calories than you burn from whatever source, carbs, protein or fat, you will gain weight. So cutting out carbs or fat does not necessarily mean cutting out calories if you are replacing them with other foods containing the same amount of calories. Any food can cause weight gain if you overeat (yes, even broccoli)!
While we can most certainly survive without sugar, it would be quite detrimental to eliminate carbs entirely from your diet. Sources of carbs such as starchy foods, vegetables, fruits, legumes and dairy products are an important source of nutrients such as calcium, iron and B vitamins. Cutting out these foods from your diet could put you at increased risk of a deficiency in these nutrients plus many others, which can lead to a variety of health issues. Eating enough fibre will also be difficult, which is important for a healthy digestive system and to prevent constipation.
Carbohydrates, fat and protein all provide energy, but muscles rely on carbohydrates as their main source of fuel. However, muscles have limited carb stores (glycogen) and they need to be replenished regularly to keep your energy levels high. A diet low in carbs can lead to early fatigue during training and delayed recovery. If the body has insufficient carbohydrate intake or stores, it will consume protein for fuel which is problematic as the body needs protein to retain/build muscle mass. Additionally, without sufficient glucose, the central nervous system suffers, which may cause dizziness or mental and physical weakness.
DOES CARB CHOICE MATTER?
There are no “good” or “bad” carbs, but there certainly ones that provide a greater benefit from a nutritional standpoint. Fruit, vegetables, pulses and starchy foods (especially wholegrain varieties) provide a wider range of micronutrients (such as vitamins and minerals) which can benefit our health. The fibre content in these foods can help to keep our digestive tracts healthy and helps us to feel fuller for longer. Sugary foods such as lollies, pastries and soft drinks are often referred to as “empty calorie” foods because they don’t offer much else besides pure energy. In addition to this, these carbs are often not very filling, which results in people consuming higher amounts of them. For a healthy sustainable diet, I recommend getting 80-90% of your carb intake from whole, nutritious foods and the remaining 10-20% can be used for more processed foods.
HOW MANY CARBS SHOULD I EAT?
The “optimal” carbohydrate intake for you depends on numerous factors, such as age, gender, metabolic health, physical activity levels, and personal preference.
Check out my Custom Nutrition Plan or Macronutrient Calculation to have your calorie and macronutrient intake calculated for you based on your goals or contact me today if you have any questions about carbs!