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Why Sugary Drinks Are So Bad for the Brain

... and why "sugar-free" options may not be much better.

Key points

  • The worst food for brain health may in fact be sugar-sweetened beverages (SSBs).
  • SSB consumption is linked to a higher risk of metabolic dysfunction, stroke, dementia and depression.
  • SSBs to avoid include soda, energy drinks, coffee drinks, many fruit juices, and sports drinks.
  • While artificial or alternative sweeteners sound good, the best bet is to decrease your dose of sweet liquids.
Tim Samuel/Pexels
Tim Samuel/Pexels

Each day, we consume roughly four pounds of food and around two to four liters of fluid. That is a ton of data for our bodies to process, all of which can impact our brain health and function.

Unfortunately, we’re, on the whole, consuming more of our calories from junk sources and less from the types of foods and beverages linked to better brain health. In fact, a 2021 study in JAMA showed that in youths aged 2-19, almost 70 percent of their calories came from ultra-processed (aka junk) food. Among all these junk calories, there may be nothing more concerning for brain health than sugary beverages.

Sugar-sweetened beverages (SSBs) are a large group of drinks that are sweetened with various forms of sugar (for example, glucose, fructose, corn syrup, high-fructose corn syrup, molasses, corn sugar, and so on). SSBs are incredibly pervasive and are among the most popular drinks on the market. These brain-draining liquids are marketed as energy drinks, coffee beverages, soda, fruit drinks, teas, sports waters, and more.

According to research published over the last decade, about half of adults drink an SSB on a given day, a rate that increases to 63 percent in youth. Statistically speaking, it’s likely you consume these toxic drinks regularly. So, why are SSBs so bad for the brain?

1. They destroy healthy metabolism.

One of the most consistent findings in the research on SSBs is their association with unhealthy weight gain. Across children and adults, more SSBs means more weight gain (and removal leads to weight loss). Compelling research links SSB consumption with the risk of developing type 2 diabetes (one analysis showed for every 250 mL consumed a day, the risk of getting diabetes increased by 15 percent).

Concerning data shows that as we gain weight, our brains may have more trouble with healthy sensing of sugar from SSBs, leading to a feed-forward cycle. Obesity, diabetes, and general metabolic dysfunction all result from SSB consumption, and each of these is a well-established risk factor for brain conditions like depression and cognitive decline.

2. They increase the risk of brain vascular diseases like stroke.

Vascular issues, including high blood pressure and stroke, are incredibly damaging to the brain. Each of these can contribute to dementia, and each of these is tethered to our food and beverage choices.

Unfortunately, our consumption of SSBs is a major risk factor for each of these. In a 2023 meta-analysis of 72 articles, higher consumption of SSBs was linked to increased risk of stroke, hypertension (high blood pressure), and dying earlier from vascular disease.

3. They increase the risk of dementia.

By damaging metabolic health, messing with the brain’s vascular system, and increasing inflammation, it’s no wonder that a higher consumption of SSBs is linked to a higher risk for dementia. Right now, there are over 50 million people with dementia, and that number is slated to hit over 150 million in the next few decades. If cutting back on SSBs could offset even a fraction of this, we really need to be taking this seriously.

4. They increase the risk of depression.

Depression affects hundreds of millions of people around the world. For the most part, standard care is based on medications and psychotherapy. While these options can be effective for some, it’s also true that we need more emphasis on depression prevention.

This is where SSBs come into the picture. SSB consumption is linked to a significantly higher risk of becoming clinically depressed. Those drinking three cans of cola a day may have as much as a 25 percent higher risk for depression. Again, metabolic and inflammatory factors may be at play.

What Should You Do About This Information?

Many health experts like to talk about “everything in moderation.” The reality is that there’s no amount of sugary beverage that’s good for most people. Almost nobody benefits from all the extra calories, and more importantly, the sugar spikes, metabolic dysregulation, and inflammatory and vascular issues resulting from SSB consumption are likely to have a compounding effect over time. This means dramatically cutting back or cutting out SSBs from your life is a good plan.

Can You Just Replace Them with Artificial Sweeteners?

One of the most popular questions coming from this compelling research on the harms of SSBs is whether we can simply switch out sugar for a sugar alternative. With artificial sweeteners like aspartame and sucralose available in restaurants and grocery stores across the country, they must be safer, right?

Unfortunately, a number of recent studies have shown that even these zero-calorie sweeteners may be harmful, increasing the risk for diabetes, high blood pressure, stroke, dementia, depression, and more.

What About “Natural” Sweeteners?

There’s a lot of diversity in the “natural” sweeteners that we can use in our beverages. They range from sugar alcohols like erythritol and xylitol to plant-derived zero-calorie options like stevia and monkfruit to rare sugars like allulose. A popular discussion here also concerns the healthiness of brown sugar versus white sugar, or whether date sugar, coconut sugar, or honey is indeed better for us than cane sugar.

Though the research is still evolving here, here’s one way to look at these options:

  • Limit: Sugar alcohols (erythritol, xylitol), date sugar, coconut sugar, dates, maple syrup
  • Potentially OK in moderation: Honey (some research even suggests metabolic benefits)
  • Best of the low-calorie sugar alternatives: Stevia, allulose, monkfruit

The Overall Best Options

As much as our brains want to cheat with sugar alternatives and potentially healthier sugars (like honey), the truth is that we’re best served by teaching our brains not to crave and need sugar with our beverages. This can be a tough transition and may take some time, but it’s well worth it for your brain and overall health.

Your healthiest options:

  • Unsweetened tea and coffee
  • Flavored (but unsweetened) sparkling water
  • Eating whole fruit

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