This has been bugging me for a while. As summer approaches, a lot of people are posting their diets for critique. A lot (because they are on a limited time scale) are fairly low calorie, circa 1200-1800kcal per day. I've seen quite a few regular posters on here suggesting that low calorie diets lead to "starvation mode", well I wanted to point out that this is simply untrue. True "starvation mode" only occurs when you get below the essential level of fat that a human should carry, for a man this is below 5%. Not many people (if any at all) will approach that level of leanness, but some competitive bodybuilders might approach that for a few days around a show. Essentially, what really happens when you drop calories low is that you subconsciously drop activity to match (unless you're actively monitoring it that is). The "Energy Out" side of the energy balance equation reduces, and therefore you see a drop off in weight loss. You are NOT entering starvation mode when this occurs. Other annoying things like water weight and the fact that fat loss is never linear can make people think their approach isn't working. Full anyone interested the full article is here: Are you in starvation mode or starving for the truth?