Sugar's Effect On The Body When Tired

Sugar provides a temporary source of energy when you're tired, which is why you might grab a candy bar or cupcake in late afternoon. However, it actually can increase your feeling of fatigue a few hours later. Common sources of sugar include soda, candy, white bread, cereals and desserts.

Fatigue

You may experience fatigue when you are overtired or overworked. Robert D. Sheeler, M.D., notes on the Mayo Clinic website that fatigue is one of the most common complaints physicians receive. Fatigue is a feeling of tiredness and lack of energy. It may have emotional causes like boredom or feeling burdened, or it may be a symptom of a medical condition like anemia, depression or thyroid problems. See your doctor if you are experiencing fatigue to rule out any medical causes.

Sugar

When you eat sugar, your blood sugar levels rise and your body produces insulin to process the sugar into energy. Your body also converts complex carbohydrates and protein into energy, but sugar produces a more immediate effect because it takes less time to digest. Unlike other sources of energy, sugar provides no added nutritional benefits such as vitamins and minerals. The American Heart Association advises women to limit their added sugar intake to 6 tsp per day and men to 9 tsp per day.

Immediate Effect on Tiredness

When you first eat sugar, you may feel a spike of energy. A study comparing the energy levels of people who consumed a candy bar versus people who exercised found that the immediate impact of the candy bar was increased energy. The amount of increased energy was slight, but it lasted at least 20 minutes.

Long-Term Effect on Tiredness

The same sugar that gave you energy might be responsible for your increased tiredness later on. In the candy bar study, most participants reported having less energy one to two hours after eating the candy bar than they had beforehand. In the article "What Can Be Done to Prevent the 'Mid-Afternoon Slump,'" Dr. John Briffa states low blood sugar levels contribute to fatigue. When you eat sugar, your body produces insulin. The more sugar you eat, the more likely your body is to overcompensate by producing too much insulin. You might experience low blood sugar levels within two to three hours and as a result have decreased energy.