Dr. Donald Grant has broken down the rapid bodily changes that follow a single can of sugary soda.
The GP and Senior Clinical Advisor at The Independent Pharmacy, a UK-based online pharmacy, detailed how the effects begin within minutes and can leave drinkers feeling drained before they’ve finished the can. His analysis comes amid ongoing public health guidance from the Centers for Disease Control and Prevention urging Americans to limit sugar-sweetened beverages.
The sugar hits fast because it is already dissolved in liquid. “Within minutes of drinking a sugary soda, the sugar is absorbed rapidly into the bloodstream because it’s already in liquid form and needs very little digestion,” Dr. Grant said. That speed triggers a sharp spike in blood sugar, which prompts the pancreas to flood the body with insulin to push levels back down.
But the pancreas is not the only system responding. The carbonation that gives fizzy drinks their bite releases carbon dioxide gas in the stomach, which Dr. Grant said can produce bloating, burping or general discomfort. People prone to acid reflux may see their symptoms worsen as the gas expands and pressure builds.
The insulin surge then creates a second, opposite wave of effects. “Not long afterwards, you often get the flip side of the sugar spike,” Dr. Grant explained. He said energy levels can dip, leaving some people feeling “tired, foggy or a bit irritable.” That crash, he added, is part of what can make fizzy drinks easy to fall into a habit with, as the body prompts for another hit to climb back out of the slump.
A standard 12-ounce can carries roughly 10 teaspoons of sugar and about 150 calories with little nutritional value to show for it. The CDC specifically advises limiting or avoiding regular soda and similar beverages because of that sugar and calorie load. Regular consumption has been tied to weight gain, and frequent intake of sugar-sweetened drinks has also been linked to type 2 diabetes, heart disease, non-alcoholic liver disease and gout.
The damage can show up in dental exams too. The combination of sugar and acid in soda contributes to tooth decay and enamel erosion over time, adding oral health to the list of concerns.
Dr. Grant was careful to draw a line between habitual and occasional drinking. “None of this means an occasional soda is something to worry about,” he said. He warned, however, that regular consumption can contribute to weight gain, tooth decay, enamel erosion and a higher long-term risk of type 2 diabetes.
For those looking to cut back, the CDC recommends plain tap, sparkling or bottled water as the simplest swap. Water can be flavored naturally with cucumber, berries, lemon or lime. Plain sparkling water mixed with a splash of 100% fruit juice can also offer a fizzy alternative without the sugar load.
Dr. Grant pointed to similar substitutes. He suggested sparkling water, diluted juice or sugar-free alternatives as ways to reduce sugar intake, while noting that water remains the best everyday option.
The CDC’s broader guidance frames sugar-sweetened beverages as one of the largest sources of added sugars in the American diet, making them a frequent target in public health campaigns aimed at reducing chronic disease risk.