The relationship between diet and acne is unclear, as there is no high-quality evidence that establishes any definitive link between them.  High-glycemic-load diets have been found to have different degrees of effect on acne severity.  Multiple randomized controlled trials and nonrandomized studies have found a lower-glycemic-load diet to be effective in reducing acne.  There is weak observational evidence suggesting that dairy milk consumption is positively associated with a higher frequency and severity of acne.  Milk contains whey protein and hormones such as bovine IGF-1 and precursors of dihydrotestosterone.  These components are hypothesized to promote the effects of insulin and IGF-1 and thereby increase the production of androgen hormones, sebum, and promote the formation of comedones.  Available evidence does not support a link between eating chocolate or salt and acne severity.  Chocolate does contain varying amounts of sugar, which can lead to a high glycemic load, and it can be made with or without milk. Few studies have examined the relationship between obesity and acne. Vitamin B12 may trigger skin outbreaks similar to acne (acneiform eruptions), or worsen existing acne, when taken in doses exceeding the recommended daily intake.  Eating greasy foods does not increase acne nor make it worse.