Lung function - Studies that looked at the effects of marijuana show paradoxical effects. Thus, some studies show that the drug dilates breathing passages in the lungs, while others point to a significant degree of airway obstruction. Smoking pot yields more tar than cigarettes, and a 1988 University of California at Los Angeles study found that smoking pot releases five times as much carbon monoxide into the blood, which ties up oxygen, and three times more tar than cigarettes. Another study showed that three to four joints a day can produce as much lung damage as 20 tobacco cigarettes.
Frank Zane shouldn’t be the standard which we use as a “cut off” to tell whether or not an athlete is natural. While he was on roids and fairly impressive, at 5’9, 185 lbs, 5% bodyfat, he only had an FFMI of around 26. While this is high, easily over the broscience “limit” of 25, several known natural bodybuilders in early bodybuilding history have surpassed it, with Jack Delinger hitting an FFMI over 28 in 1949 and George Eifferman hitting around in 1948. These and other high numbers were obtained before steroids were even available to the public, before Russians even gave steroids to their Olympic team. Likewise, these were before leg development was emphasized in bodybuilding to the degree it is now, so these people may have been able to attain higher levels of physical development than even then. Now, your current numbers list Lazar at 200 pounds at 5’9 and 5% bodyfat. This would put him at an FFMI of around 28, which is hard to achieve, but believable because of the above examples. However, other sources, such as SimplyShredded and HealthyCeleb put him at 5’11” and 195 lbs, which at a bodyfat percentage of 5%, would put him at an FFMI of – which is well under previous natural achievements. At the end of the day, he may be natural, even though it is way easier for him to be where he is with the help of steroids.