This is the 1973 Loma Linda sugar study. Sugars (glucose, fructose, sucrose, honey, orange juice) all crippled the functionality of phagocytes. Significantly for 1-2 hours after eating, with negative effects lasting up to 5 hours after consuming sugars. Phagocytes are part of our immune system. They’re white blood cells that, to protect you, “eat” (think: Pac Man) pathogens: bacteria, viruses as well as dead and dying cells - and more. SO, basically, if you’re eating or drinking sugary drinks all day you are crippling your immune system. (And also inhibiting Vitamin C absorption! But that's a separate entry.)
"Oral 100-g portions of carbohydrate from glucose, fructose, sucrose, honey, or orange juice all significantly decreased the capacity of neutrophils to engulf bacteria as measured by the slide technique. Starch ingestion did not have this effect. The decrease in phagocytic index was rapid following the ingestion of simple carbohydrates. The greatest effects occurred between 1 and 2 hr postprandial, but the values were still significantly below the fasting control values 5 hr after feeding (P < 0.001). The decreased phagocytic index was not significantly associated with the number of neutrophils. These data suggest that the function and not the number of phagocytes was altered by ingestion of sugars. This implicates glucose and other simple carbohydrates in the control of phagocytosis and shows that the effects last for at least 5 hr. . On the other hand, a fast of 36 or 60 hr significantly increased (P < 0.001) the phagocytic index."