When a calorie is not just a calorie: Sugar!

For many years, nutritionists and doctors thought that a calorie from one source- say fat- was essentially equal to another calorie from a different source- say protein.  There is plenty of evidence now that this is not true.  First, a little background; a calorie is a unit for measuring the amount of heat required to raise the temperature of one gram of water one degree Celsius. For example, in a laboratory we could actually ignite a gram of fat, and it would yield the equivalent of 9 calories of heat sufficient to heat 9 grams of water by one degree Celsius.  If we did the same with a protein or a carbohydrate, we would get 4 calories, while alcohol would give us 7 calories. So if we wish to maintain a proper body weight, we should aim to be isocaloric. That is to say, we should consume the same number of calories as we “burn” through our activities, both mental and physical. However, there is much more to the story.

There are many complicated biochemical processes that occur in our cells when we consume calories from different sources. These processes affect our mental and physical health, both in the hours after we eat and over our lifetimes.  This is why the balance or proportion of energy sources in our diets (fats, protein, carbohydrates, including sugars, and alcohol) is really important. And because the way we eat (think processed food made in factories, fast-food restaurants) has changed so dramatically, it is essential that we understand the health implications and make a sustained effort to eat a diet that is truly balanced.


So now we get to the main topic of this week’s post; sugar!  A great deal of recent research tells us that our bodies respond to sugar in very unhealthy ways. In fact, in many ways our cells metabolize sugar much like alcohol, and with similar consequences! By this, I mean that diets that are high in sugar promote chronic disease by causing weight gain, fatty liver, generalized inflammation, insulin resistance, Type 2 diabetes, hypertension and heart disease.  And we are now often seeing these effects in very young children!

And metabolically speaking, our bodies don’t differentiate between added and natural sugars. This is really important to understand. To our bodies, a gram of white table sugar (from beets or cane) is the same as a gram of honey, or a gram of sugar in fruit juice. So how do we start to correct this situation?

First, be aware that about 75% of the processed foods you buy at the supermarket contain added sugars.  This means if you or your children are eating a lot of food that comes in packages or bottles (think sauces) that were made in a factory, you are most likely getting a lot more sugar in your diet than you realize.   This is because food companies know that humans like sugar, and we will buy more of their products if they are sweet! The reality is that sugar can make pretty awful things taste good. This is especially true with “low-fat” foods that often taste very bland unless large amounts of sugar are added.

Second, about half of the added sugar we consume comes from sweetened drinks, much of it in soft drinks, but also in sweetened tea and coffees, fruit juices and fruit drinks, and sports drinks.  We need to try to eliminate these drinks from our diets and our children’s diets. Yes, it’s time to start drinking more plain water again!


There is strong evidence that improvements in health can be observed in just a few days after a significant reduction in the amount of sugar in our diets. And recently, the US Food and Drug Administration (FDA) has issued specific guidelines for the amount of sugar that we should be getting. However, I will save this information for my next post. Stay tuned!




Leave a Reply

Your email address will not be published. Required fields are marked *