Not Keto
Sourdough Bread
17.90g net carbs per 1 slice
Sliced from a tangy fermented loaf, one piece packs 17.9 g net carbs, which can eat up most of a strict daily keto allowance in a single bite. The fermentation does nothing to lower the carb count here, so skip it and reach for an almond or coconut flour bread instead.
By MeKeto Editorial · Last updated July 2026
Nutrition Facts
Fits My Daily Budget?
Set your daily net carb limit to see how one serving fits.
One serving uses 89% of your 20g daily budget.
Plan the rest of your day
Good to Know
The slow fermentation breaks down some starches and can give sourdough a gentler blood sugar curve than standard white bread, but the carbs are still there in full. Watch for bakery loaves cut thick, since a hearty deli slice can run well past the 36 g serving here and push net carbs over 25 g. If you want the sour flavor without the load, look at almond flour or coconut flour mock loaves, which cut net carbs to roughly 2 to 4 g per slice.
Is Sourdough Bread Keto? The Full Answer
Sourdough Bread contains 17.90g net carbs per 1 slice (18.70g total carbs minus 0.80g fiber). Sliced from a tangy fermented loaf, one piece packs 17.9 g net carbs, which can eat up most of a strict daily keto allowance in a single bite. The fermentation does nothing to lower the carb count here, so skip it and reach for an almond or coconut flour bread instead.
On a standard ketogenic diet, most people target 20-25g net carbs per day. A single serving uses 89% of a 20g daily carb limit. If you are following a strict ketogenic protocol, reach for a lower-carb option instead.
Better Keto Swaps
Here's the problem with a slice of sourdough: it lands at 17.9 g net carbs, and that one slice alone can eat your whole daily keto budget. Swap it out instead. Try a slice of almond flour bread, which usually runs about 2 to 3 g net carbs and gives you a chewy base for sandwiches without the wheat. Cloud bread (oopsie bread) made from eggs and cream cheese is another option, sitting close to 1 g net carbs per piece and great when you want something light for a quick open-faced bite. If you miss the tang and structure of a real loaf, a flax and psyllium husk bread holds up well for toasting and comes in around 1 to 2 g net carbs per slice, with the fiber doing some of the heavy lifting.
Measure Your Ketone Levels
A blood ketone meter reads beta-hydroxybutyrate from a finger prick, the marker that defines nutritional ketosis at 0.5 to 3.0 mmol/L. Urine strips measure acetoacetate instead, which drops off once you are fat-adapted. Keto-Mojo makes a blood meter.
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