Possible side effects of using agave nectar include increased insulin resistance, weight gain and increased triglycerides, according to Ann Jamerson for SFGate. Many agave nectar products contain up to 90 percent fructose, and high levels of blood fructose have adverse effects on health.
Long-term insulin resistance eventually impairs the body's ability to metabolize glucose, explains Jamerson. If untreated, insulin resistance combined with high blood sugar can cause prediabetes and then Type 2 diabetes. Agave nectar has a lower glycemic index, which means spikes in blood sugar are not as extreme or damaging. However, agave nectar is not considered a healthy alternative to regular sugar by many health experts. As of 2015, not enough studies have been conducted to support the health benefit claims of agave nectar.
The American Diabetes Association recommends treating agave nectar like sugar because of the adverse effects of its high fructose content. Rather, it is best to eat naturally sweetened foods such as fruit and small amounts of honey, says WebMD. Agave nectar has around the same amount of calories per serving as regular sugar and is actually much sweeter. Due to its sweetness, it is possible to use a small amount of agave nectar for many recipes.