There can be both pros and cons to drinking orange juice on an empty stomach.
An 8-ounce glass of orange juice provides nearly 29 grams (g) of carbohydrates, 21 of which come from sugar.
Sugar is a type of carbohydrate, which is the body’s preferred source of energy. That means drinking orange juice by itself could give you a quick pick-me-up in the morning.
This is especially true because orange juice has minimal amounts of fiber, which would otherwise slow down the body’s absorption of sugar.
According to Toby Amidor, MS, RD, a registered dietitian and cookbook author, this hit of energy can be helpful if you’re headed for an A.M. workout.
“OJ is a good pre-workout snack as it is easily digestible, which is what you want pre-workout— especially within 30 minutes of the activity,” Amidor told Health.
Essentially, the carbs in orange juice can replace glycogen (energy) stores and restock fluids that your body may have lost overnight, setting you up for a better workout.
When you drink your orange juice without food, there’s nothing to inhibit or compete with your body’s absorption of its nutrients—that goes for carbs, antioxidants, and vitamin C.
“A cup of freshly squeezed orange juice can contain over 100% of the recommended daily vitamin C intake for adults,” said Jennifer Phan, MD, gastroenterologist with Hoag Physician Partners in Irvine, CA.
That’s a good thing for your immune system—vitamin C helps protect existing immune cells and promote the production of new ones, Amidor said.
“The stomach does not need food present for vitamin C to be absorbed, so orange juice still delivers its antioxidant and immune-supporting benefits,” Phan told Health.
The same is true for other antioxidants in orange juice, including hesperidin, a phytonutrient which helps “protect the body’s cells against damage caused by free radicals,” Amidor explained. Hesperidin may also be good for heart health—research from 2021 found that hesperidin in orange juice improved the function of the endothelium, or the layer of cells that line the blood vessels.
Drinking orange juice solo won’t change anything, she said, so you’ll reap all of these benefits even on an empty stomach.
There’s a reason juices are often recommended as a quick treatment for low blood glucose (hypoglycemia): They rapidly raise blood sugar.
“The natural sugars in orange juice are absorbed quickly,” Phan explained. “Without food to slow the process, this can lead to a spike in blood sugar.”
Blood sugar spikes may sometimes lead to feelings of thirst, tiredness, headaches, blurred vision, or frequent urination. However, for most people, an increase in blood glucose isn’t too worrisome.
“The boost in natural sugar will give you a short spike, but it will go right back down,” Amidor said.
And even though drinking orange juice on an empty stomach may raise your blood sugar briefly, research suggests there’s no association between drinking 100% fruit juice and developing diabetes, she added.
“If you’re worried [about your blood sugar], then stick to one serving and consume with food or in a smoothie with other foods,” Amidor suggested.
With a pH level of about four, orange juice is certainly acidic. So for some people, drinking it by itself could cause gastrointestinal issues.
“On an empty stomach, there is no food to buffer its acidity,” said Phan. “This can lead to irritation of the stomach lining in people who are sensitive. It can also trigger heartburn and acid reflux.”
However, Phan noted that this is most common in people with underlying conditions, including gastroesophageal reflux disease (GERD), gastritis, ulcers, or irritable bowel syndrome (IBS).
The same acidity that could irritate your stomach could harm your tooth enamel, too.
“When you drink orange juice on an empty stomach, your body produces less saliva, which is what protects the teeth,” Michael Wei, DDS, founder of Manhattan Cosmetic Dentist, told Health.
When this happens, the acid from orange juice sits on the teeth, raising the risk of enamel erosion and tooth decay, he explained. A 2021 study found that, in the lab, commercially prepared grape, citrus fruit, strawberry, and orange juice increased the damage to tooth enamel and dentin (the material beneath the enamel).
To minimize these effects, Wei recommended drinking orange juice through a straw or following it up with a glass of water.
