Does avocado help lower your blood sugar spike after a meal?
If you eat half or a whole avocado in place of carbohydrates, there is preliminary evidence that your post-meal blood sugar spike will be lower. If you simply add avocado to what you are already eating, that effect does not appear to be present.
Avocado used as a partial replacement for carbohydrates in a meal significantly reduced the post-meal blood sugar spike in people who were overweight or obese. Both half an avocado and a whole avocado produced this effect. One of the lead researchers on that study is a member of an avocado nutrition advisory board, which is worth bearing in mind when interpreting the findings.
Another study looked at what happens when avocado is simply added to lunch rather than substituted for something else. No effect on blood sugar was seen, although that meal contained 112 kcal more than the control meal. Whether the extra calories skewed the result is uncertain.
Avocado appears to do little for fasting blood sugar. A well-designed study in which adults with elevated cardiometabolic risk ate one avocado daily for three weeks showed no difference in fasting glucose or insulin. That study was partly funded by the avocado industry. In women with type 2 diabetes, a diet rich in avocado and olive oil likewise did not differ from a high-carbohydrate diet after four weeks, although that study was very small at twelve participants.
Among people of Hispanic descent with type 2 diabetes, eating more avocado was linked to a lower HbA1c (a measure of average blood sugar over the preceding months) and lower fasting glucose. However, this is an observational association: it may simply reflect the fact that people who eat a lot of avocado tend to have healthier lifestyles in general.
The conclusion is therefore nuanced. Avocado as a replacement for carbohydrates in a meal has a credible first signal for a lower post-meal blood sugar spike, but only when carbohydrates are actually displaced. Simply adding an avocado to your usual meal does not appear to produce the same effect. On fasting blood sugar, avocado likely has little impact.
The evidence rests on a handful of small human studies with varying outcomes depending on the study design: are carbohydrates replaced by avocado, or is avocado simply added? Two studies have industry ties, which reduces confidence in precisely those positive findings. One large observational study in Hispanic people with type 2 diabetes shows an association but cannot establish cause and effect.