As a corollary to the previous article (see “Calorie Restriction and Longevity – The Role of Sugar“), we will further refine our diet to capture benefits attributed to calorie restriction. As described in detail here, calorie restriction and longevity are linked by multiple factors.
With respect to diet, we will logically derive through a series of negations what food does not contribute to longevity based on the latest discoveries in nutritional science. If we are advised to minimize simple sugars in our diet because of the series of problems that elevated insulin levels bring, then we should as a point of logic also avoid carbohydrates that easily break down into glucose.
The Glycemic Index
Fortunately we have a tool to measure the pure glucose equivalent of eating any type of food in isolation. A Glycemic Index (GI) is a number that represents the rise in blood sugar level from any food 2 hours after consumption. With pure glucose set at 100, the GI indicator becomes a relative measure of how quickly one unit of carbohydrates is broken down into the harmful glucose that leads to the spike in insulin.
Due to the genetic differences and varying degrees of metabolic rates and insulin resistance, the level of GI is not meant to be an accurate threshold from which we can target an insulin response. It is meant to be an estimator to rank foods by how easily each unit of carbohydrates is broken down.
A related measure adjusts the GI to the quantity of carbohydrates in the typical serving of the food that is consumed. The Glycemic Load adjusts GI by multiplying it by the number of carbohydrates in a typical serving and dividing by one hundred.
A Glycemic Load of less than 10 is considered low. However, the number of servings and what other food mix is consumed at the same time matter. Furthermore, tolerance differs from person to person. A physically active person that regularly depletes glycogen can tolerate higher levels of Glycemic Load.
To take an example, carrots have a similar GI as white pasta: approximately 47. Recall that this measure is per unit of carbohydrates. To adjust for the Glycemic Load, multiply by the number of carbohydrates per serving – 6 grams for a carrot and 40 grams for a cup white pasta – and you get a Glycemic Load of 2.8 for carrots vs. 18.8 for white pasta.
While not perfect, Glycemic Load allows us to allocate our carbohydrate consumption to nutrient-rich foods like fruits and vegetables. As an added benefit, antioxidants from this food group work to counter any oxidative stress that results from metabolizing glucose.
Tricks to reduce Glycemic Load
The key to reducing Glycemic Load is to slow down absorption. The most obvious recommendation is to take time to eat your food. Mixing your meal with ingredients that traps carbohydrates like vinegar, fiber, fats and protein can also slow down absorption such that you can strategically avoid the insulin spike. However, if fats are consumed along with a high overall level of carbohydrates, the insulin spike will signal your fat cells to absorb both and you lose the benefit of the low Glycemic Load calculated for each ingredient.
The special case of alcohol
Research also points to low-carbohydrate alcohol before a meal as one way slow down absorption of carbohydrates from the meal. This is possibly one factor in wine’s link to longevity, a subject deserving its own article. It is also why diabetics taking insulin shots or other medications are advised to be wary of hypoglycemia when consuming alcohol, which is a condition in which blood glucose levels becomes dangerously low.
However, this is not to say that you should consume alcohol in quantity. Alcohol is metabolized in the liver to produce a molecule called citrate. This molecule converts glucose into fatty acids. In small quantities and without an insulin spike, this works well to reduce glucose levels in the blood. In large quantities of alcohol consumption, the excess fat production ends up deposited in the liver, which explains why alcoholics suffer from fatty liver syndrome.
If you are like most people, it is also likely that your excessive alcohol consumption is coupled with excess carbohydrates because your body craves them when glucose in the blood is being depleted by fatty acid production in the liver. This is how we get the infamous “beer belly.”