Cutting Out Carbs for Weight Loss
Consider Both the Glycemic Index and Glycemic Load
When I am discussing weight loss and the proper foods to eat, you will constantly hear me refer to blood sugar and hormonal balance. When explaining part of the “weight loss puzzle” to my clients, I will often detail the role of insulin, sugar and the glycemic index (GI). In addition to the glycemic index, there is another important tool of measurement called the glycemic load (GL) that can also provide beneficial information on which carbohydrates to eat and which to avoid to lose weight and burn belly fat.
The GI and GL
Both the glycemic index and the glycemic load rankings refer to carbohydrates. When carbohydrates are digested, sugar enters the bloodstream. The glycemic index ranks how quickly sugar (glucose) enters the bloodstream after a particular carbohydrate is eaten. The scenario goes like this:
- If you eat a food item that is high on the glycemic index such as processed flours or white sugar, blood sugar rises too quickly. In response to this spike in blood sugar, your brain signals your body to secrete a hormone called insulin.
- One of insulin’s roles is to bring sugar out of the bloodstream, primarily by converting the excess sugar into fat and storing it in your body.
- A greater rate of increase in blood sugar leads to a greater insulin release, more storage of fat and then a drastic lowering of blood sugar levels. This is what leads to an energy rush followed by lethargy and hunger after eating a candy bar.
- This is significant because excess insulin secretion can result in various ill health effects such as fatigue, weight gain in the abdominal region and, eventually, type 2 diabetes.
Highs and Lows
For ranking purposes, the glycemic index is divided into three categories: low, medium and high. Food is categorized from low to high on a scale of 0 to 100, depending on its effect on blood sugar levels. Foods that are lowest on the glycemic index have the slowest rate of glucose entry into the bloodstream, and therefore have the lowest insulin response. The categories are:
- Low (up to 55)
- Medium (56 to 70)
- High (over 70)
Fiver, Protein and Fat
Fiber, protein and fat all slow down the entry of glucose from a particular food into the bloodstream. Most vegetables, beans and whole grains are full of fibre, which is reflected in their lower glycemic index rating. For example:
- Green peas 48
- All-bran 38
However, processed foods (e.g., white flour) usually contain little to no fiber and therefore tend to have a higher glycemic index rating. For example:
- Strawberry cupcake 73
- White bread 73
One limitation of the glycemic index is that it does not take into account how much sugar a particular food contains -- it is only a reflection of how quickly the sugar is absorbed. For example, the sugar in carrots is readily absorbed into the bloodstream and they are therefore ranked high on the glycemic index (74). This has given carrots some undeserved bad press. While many choose to avoid eating carrots due to their higher glycemic index rating – I assure you, I have not had one client who has gained weight from eating too many carrots!
This is where the glycemic load of a particular food becomes very useful. In fact, the glycemic load and glycemic index can be used in tandem to make healthier food choices.
The glycemic load takes into account not only how quickly a certain food is converted into sugar in the body but also how much sugar (carbohydrate) a particular food contains. To figure out the GL of a food product, multiply the glycemic index value of a food by the amount of carbohydrate per serving and divide the result by 100.
If you consider the glycemic index of watermelon (76), you may avoid it altogether in your diet. However, a cup of watermelon has only 11 carbohydrates and the glycemic load is 8, falling into the low category.
Here are examples of the glycemic load of some foods:
- Steamed Broccoli (1/2 cup) - 1
- Cashews (2 oz) – 3
- 2% Milk (1 cup) – 4
- Ice cream (1 cup) – 8
- Apple juice (1 cup) – 12
- Cooked oatmeal (1 cup) – 16
- Corn flakes (1 cup) - 27
- Raisins (1/2 cup) – 28