Black coffee barely moves the needle. The "healthy" oat milk in your latte and the orange juice next to your breakfast are near the top of the list. If you're trying to figure out the best drinks for diabetics, for prediabetes, or just for a steadier morning, the honest ranking looks nothing like the one on the front of the cartons.
Signos measured it. Not label sugar grams, not marketing claims, but the average glucose spike logged by tens of thousands of members wearing a continuous glucose monitor. Some of these drinks were logged more than fifty thousand times. So when we say black coffee lands at the bottom and does coffee raise blood sugar, turns out to be a question with a reassuring answer, that's real data talking, not a guess.
We ranked twelve popular drinks from the smallest average spike to the largest. A few of the results will change how you order. The trendy oat milk spikes more than whole milk. A glass of dry wine is steadier than a beer. And in almost every case, the culprit isn't the drink itself. It's what you add to it. Here's the full list, and what to drink instead when a favorite lands higher than you'd like.
How We Ranked These (The Data Behind Atlas)
Every number here comes from the Signos Food Atlas, our library of foods and drinks scored by real glucose response. Each figure is an average glucose peak in mg/dL, drawn from members' logged servings and measured by CGM, so it reflects what actually happened to people, not what a nutrition label predicts.
For each drink we track that peak, plus glycemic index and glycemic load, and the sample size. The beverage set is one of the largest in the Atlas: black coffee alone spans more than 35,000 logs, and the almond milk and protein shake pages run past 40,000 each. Big samples are why the surprises below hold up.
It's worth saying why we don't just rank by the sugar on the label. Two drinks with the same grams of sugar can behave very differently once fiber, fat, protein and how fast you drink them get involved. Measured glucose response folds all of that in. That's how a drink marketed as healthy can quietly outspike one that isn't, and how the label can be technically accurate and still misleading about what happens in your body.
The Ranking: Best to Worst
Here are the twelve, from the smallest average glucose spike to the largest:
- Black coffee — +21.7 mg/dL
- Protein shake — +22.8 mg/dL
- Whole milk — +24.5 mg/dL
- Almond milk — +25.8 mg/dL
- Smoothie — +25.8 mg/dL
- Latte (plain) — +28.1 mg/dL
- Tea (plain) — +28.1 mg/dL
- Dry wine — +28.7 mg/dL
- Kombucha — +31.8 mg/dL
- Oat milk — +35.0 mg/dL
- Beer — +38.2 mg/dL
- Orange juice — +38.6 mg/dL
Two things jump out. The "natural" orange juice finished dead last, and the wellness-aisle oat milk finished in the bottom three, both above whole milk and dry wine. Below, the drinks grouped by where they landed.
The Low-Spike Pours
The bottom of the ranking, the steadiest drinks, is where the pleasant surprises live. Black coffee barely moved glucose (+21.7 mg/dL) and has a glycemic index of 0, with more than half of all logs staying under a +20 climb. Plain coffee is about as gentle as a drink gets.
Right behind it, the protein shake landed at +22.8 mg/dL, GI 25, another low mover (the plant-based versions ran a touch higher at +26.8). Then the dairy and nut milks. Whole milk came in at +24.5 mg/dL, and almond milk at +25.8 with a glycemic load of 0. The fat and protein in whole milk are doing you a favor here, slowing everything down.
The one-line takeaway for this group: unsweetened, protein-and-fat drinks stay flat. Keep them that way and they're your steadiest options.
The Middle of the Pack
The middle is where context starts to matter more than the drink. A plain latte sat at +28.1 mg/dL, reasonable, until it becomes a pumpkin-spice (+38) or arrives with a pastry (+45.5). A smoothie averaged +25.8, though blend it into an acai bowl and it climbs to +33.9. Plain tea matched the latte at +28.1, with a glycemic index of 0, but sweet tea rockets to +52.0 and boba to +47.2.
Dry wine belongs here too, at +28.7 with a glycemic index of 0, which we'll come back to. And kombucha landed at +31.8 mg/dL, higher than its healthy reputation suggests, thanks to the sugar that feeds the fermentation (the hard kombucha versions actually logged lower, around +23).
The Top Spikers
The top of the ranking is where the "healthy" labels break down. Oat milk spiked more than dairy at +35.0 mg/dL, GI 60, with a glycemic load of 11. The oats get broken down into fast-digesting sugars during processing, which is why the wellness favorite outspiked whole milk, almond milk and even dry wine. The barista and unsweetened versions are meaningfully lower (around +27 and +31).
Beer came in at +38.2 mg/dL, GI 66, the malt sugars showing up in the glucose curve, though light beer dropped all the way to +27.2. And the worst of the twelve was the one most people think of as breakfast-healthy. Does orange juice raise blood sugar? It topped the list at +38.6 mg/dL, with 62.3% of logs crossing +30. All the sugar of several oranges, none of the fiber to slow it down. A whole orange peaked about 7 mg/dL lower, because the fiber you'd normally chew through is exactly what juicing throws away. Same fruit, very different morning for your glucose.
Does Coffee Raise Blood Sugar?
This is the question people most want answered, and the answer is reassuring. Black coffee barely raises blood sugar at all. It has a glycemic index of 0 and averaged +21.7 mg/dL, the lowest of every drink we ranked.
So where does coffee's spiky reputation come from? What you put in it. Add sweetener and the same coffee jumped to +34.2, a swing of more than 12 points. Flavored syrups, a pastry on the side, a sugary creamer: those are the movers. The coffee is innocent.
If your morning cup spikes you, look at the add-ins before you blame the caffeine. Black, or with a splash of whole milk or unsweetened nut milk, coffee is one of the steadiest things you can drink. And if your own numbers ever disagree with that average, that's worth knowing too, which is exactly the kind of personal quirk a CGM will surface.
Does Alcohol Raise Blood Sugar? Beer vs. Wine
Alcohol is not one category, and the beer-versus-wine gap proves it. Beer vs. wine on blood sugar is a real difference: beer averaged +38.2 mg/dL, while dry wine came in at +28.7 with a glycemic index of 0.
That GI of 0 on wine is worth pausing on. Dry wine has almost no sugar, so a spike you see around a glass of wine is usually the meal it's sitting next to, not the wine itself. Beer is different: it carries malt sugars, which is why it climbs higher.
For the best alcohol for diabetics, or anyone watching their glucose, the pattern is clear. Dry wine and spirits with a zero-calorie mixer are the steadier picks. If beer is what you want, light beer logged much lower than regular, +27.2 versus +38.2, so the swap is an easy win. As always, food alongside and water between rounds do more than any single choice.
The Milk Question: Oat vs. Almond vs. Dairy
If one result rewrites a shopping list, it's this one. The milk you pour matters, and the trendy option is the biggest spiker of the three.
Oat milk peaked at +35.0 mg/dL. Whole milk, the "old-fashioned" choice, came in far lower at +24.5, and almond milk at +25.8 with a glycemic load of 0. So the wellness-aisle default outspiked the two it's usually chosen over. Does milk raise blood sugar? The dairy and nut versions barely do. The oat version genuinely does, because processing turns its starch into fast sugars.
You don't have to abandon oat milk. The barista and unsweetened versions dropped it to around +27 and +31, closer to the pack, so switching styles closes most of the gap. But if steady glucose is the goal and you're choosing purely by the number, whole milk and unsweetened almond milk are the quieter pours.
It's the Add-ins, Not the Drink
Step back and one pattern runs through the entire ranking. Over and over, the base drink is fine and the thing you add is the spike.
Black coffee at +21.7 becomes +34.2 with a sweetener. Plain tea at +28.1 becomes +52.0 as sweet tea, nearly double, and a boba tea lands at +47.2. A plain latte at +28.1 becomes +45.5 with a pastry on the side. A whole orange becomes a +38.6 glass of juice once you strip the fiber. Even a smoothie climbs when it turns into an acai bowl.
This is the angle no label will tell you, because the sugar and the syrup and the pastry are where the money is. The good news is that it hands you the lever. You rarely need to give up the drink. You need to watch what rides along with it. Unsweetened instead of sweet, whole fruit instead of juice, plain instead of flavored: small swaps, real difference.
The Best Drinks for Blood Sugar (Our Take)
If you want the short list, the data makes it easy. For steady glucose, water first, then black coffee, plain or lightly sweetened tea, a protein shake, or whole and unsweetened nut milks. When you drink alcohol, dry wine or a light beer treat you more gently than a regular beer. And the drinks to keep an eye on are the ones wearing health halos: orange juice, oat milk, sweet tea and sugary "wellness" drinks.
None of this means the higher-spiking drinks are banned. A morning glass of juice or an oat milk latte isn't a mistake to feel bad about. It's just a bigger glucose event than the marketing implies, and now you know which lever lowers it: the whole orange instead of the glass, the barista or unsweetened oat milk, the plain latte instead of the flavored one. Small trades, made with your eyes open, are the whole game.
Those are averages, though, across tens of thousands of people. Your coffee, your oat milk latte, your glass of wine will land on their own numbers, and that's the only ranking that matters for you. A continuous glucose monitor shows you exactly that, in real time. If you're curious what your daily drinks do to your glucose, you can see how Signos works and read your own response instead of a chart.
Want the full detail on any drink? Each one has its own page in the full Signos Food Atlas, with the peaks, sample sizes and swap tips laid out.
FAQ
Does coffee raise blood sugar? Black coffee barely does. It has a glycemic index of 0 and averaged +21.7 mg/dL in Signos data, the lowest of the drinks we ranked. The spike usually comes from what you add: with sweetener, the same coffee climbed to +34.2. Your own response can still differ from the average, which is exactly what a CGM reveals.
Does alcohol raise blood sugar? It depends on the drink. Beer averaged +38.2 mg/dL because of its malt sugars, while dry wine came in at +28.7 with a glycemic index of 0, meaning most of any wine-time spike is the food, not the wine. Light beer (+27.2) is a gentler choice than regular.
Which milk is best for blood sugar? By measured glucose response, whole milk (+24.5 mg/dL) and unsweetened almond milk (+25.8) were the steadiest. Oat milk was the biggest spiker of the three at +35.0, though barista and unsweetened versions land lower.
What can a diabetic drink at any time? Water, black coffee, and plain or unsweetened tea are among the steadiest options for anyone managing blood sugar. Because responses are personal, wearing a CGM is the most direct way to learn which drinks keep your own glucose steady.
Topics discussed in this article:
References
.svg)
