Glycemic Load (GL)

Short answer: Glycemic Load (GL) is a more precise indicator of a food's effect on blood sugar than Glycemic Index (GI) because it accounts for both the speed and the amount of carbohydrates in a typical serving. Foods with low GL (under 10) provide sustained energy, while those with high GL (over 20) cause a rapid spike. Practical tip: For optimal post-workout recovery, consume high-GL carbohydrates (0.8-1.2 g/kg body weight) combined with protein within 2 hours after exertion.

Glycemic Load (GL) is a measure of the overall effect of a food on blood sugar, taking into account the quantity and quality of carbohydrates in a food.

This article is part of the complete guide to proper nutrition — a fundamental guide from the expert team at Sport Zona.

What is Glycemic Load?

Glycemic Load (GL) is an indicator that combines qualitative and quantitative aspects of carbohydrates in a food. It assesses and shows how quickly carbohydrates turn into glucose in the blood. It also accounts for the amount of carbohydrates in a serving. Glycemic Index only considers the speed. This combined measure provides a more realistic picture of a food's impact on blood sugar levels after consumption.

Unlike Glycemic Index (GI), which is based on consuming 50 grams of digestible carbohydrates from a food, GL reflects the effect of a typical serving. This makes GL a more practical tool for meal planning, as it allows for the consideration of the actual volume of food consumed. Thus, GL helps in better management of the insulin response and maintaining stable blood sugar levels.

What are the advantages and disadvantages of Glycemic Load (GL)?

The mechanism of Glycemic Load is based on the fact that the effect of carbohydrates on blood sugar depends not only on their type but also on their quantity. The formula for calculating GL is: (Glycemic Index of the food * amount of digestible carbohydrates in grams in one serving) / 100. For example, watermelon has a high GI, but since it contains a large percentage of water, a typical serving of it will have a low GL due to a smaller actual amount of carbohydrates.

GL values are categorized as follows:

• Low GL: 10 or less
• Medium GL: 11 to 19
• High GL: 20 or more

Foods with low GL cause a smoother and more gradual rise in blood sugar and consequently a more moderate insulin response. Conversely, foods with high GL lead to a rapid glucose spike and significant insulin secretion. Understanding this mechanism is key to controlling energy levels and preventing sharp drops in blood sugar.

Why is it important for athletes?

Managing blood sugar levels is important for athletes as it is necessary for optimizing energy, performance, and recovery.

After training, the goal is to quickly replenish glycogen stores and minimize muscle breakdown. In this window (usually up to 2 hours after training), it is recommended to consume high-GL carbohydrates combined with protein – for example, 0.8-1.2 grams of carbohydrates per kilogram of body weight combined with 0.25-0.35 grams of protein per kilogram of body weight. This stimulates rapid glycogen replenishment and supports anabolic processes. During prolonged training, such as those lasting over 60-90 minutes, consuming 30-60 grams of carbohydrates per hour from medium to high GL sources can prevent glycogen depletion and maintain high performance.

• Glycemic Index (GI) — GI is a qualitative measure of the rate of carbohydrate absorption, while Glycemic Load combines this measure with quantity.
• Simple Carbohydrates — Simple carbohydrates often have a high GI and a higher GL due to their rapid absorption and high concentration.
• Anabolism — Controlling GL and insulin response can stimulate anabolic processes, especially after training, for muscle recovery.
• Autophagy — Managing GL and avoiding constant insulin spikes can indirectly support autophagy processes, which are associated with longevity and cellular health.