Calories are equal in terms of the amount of energy they contain, but where they come from – fat, protein, or carbohydrate – determines how they are used by the body. Some foods give us a steady source of energy, others can take us on a hormone roller coaster ride.
Foods that are quickly turned into sugars cause a spike in blood glucose levels. Insulin spikes in response, causing glucose levels to plummet. The sugar crash leaves us tired and craving more sugar, while insulin lingers in our blood and prevents us from burning fat.
Are calories bad for you? – A calorie is the amount of energy your body will gain from eating food that contains it. So no – we need energy to live! But, if you eat too many calories, your body will store the excess as fat.
Rise and fall – The peak and crash of glucose and steady rise and fall of insulin levels in the blood is traced along mealtimes during the day. Lets have a look at this example of the first half of a typical day.
8am Breakfast – A carbohydrate-rich breakfast – be it toasted bread or cereal – gives us a sugar rush and insulin levels rise. This rush can be heightened by the fruit juice we drink or the sugar we may put in our coffee.
10.30am Snack – As blood glucose plummets and lingering insulin inhibits fatty acid release, we start to feel tired and so desire a snack. Some sugary biscuits raise blood glucose again, and insulin follows in response.
1pm Lunch – By lunchtime a new sugar crash is upon us, which may tempt us to eat a high-carnohydrate lunch. And so the cycle continues, with both glucose and insulin levels spiking beyond the healthy range.
Putting on the pounds
The sugar trap quickly leads to weight gain, and being overweight can have serious health implications. These include insulin sensitivity, insulin resistance, type-2 diabetes, heart disease, some types of cancer, and stroke. To avoid obesity, it is vital to keep insulin levels low, and one way of doing that it is through a low-carbohyrdate diet.
Storing fat – When we put on fat, we don’t increase the number of fat cells in our body. The same fat cells just get bigger as they accumulate more fat deposits.
High protein diet – To cut out carbohydrates, some diet promoters recommend getting calories from protein and healthy fats instead. You can follow a diet in phases designed to train your body to start burning fat and rely less on carbohydrates.
Low-carbohydrate diets – A popular, if controversal, way out of the sugar trap is to limit our consumption of carbohydrates, which are otherwise broken down into sugars and stored as fat. By doing so we avoid the glucose-insulin roller coaster that ends in sugar cravings and increased fat storage. Keeping sugar and insulin levels within a healthy range enables fat, rather than glucose, to be used as an energy source.
Releasing fatty acids – When blood glucose is maintained at a healthy level, insulin levels remain low. This allows the release of fatty acids from fat cells – a process that is otherwise inhibited by insulin.
Producing ketone bodies – Unlike other tissues, the brain can’t use fatty acids as an energy source. So when blood glucose is low, the liver begins to convert fatty acids into ketones bodies – molecules that provide energy for brain cells.