 In a critique of the scientific validity of the Dietary Advice in Men's Health magazine, they discovered nuggets like this, claiming meat can give men a testosterone boost, which we've known for a quarter century, that a meal with that much fat drops testosterone levels nearly a third within hours, in fact a significant drop of both free and bound testosterone in the bloodstream, within just an hour of it going in one's mouth, whereas a low-fat meal, mostly carbs, has no such effect. Based on in vitro studies on the effects of fat on testical cells in a petri dish, they suspect fat in the blood may actually suppress testosterone production in real time. But even holding fat levels the same, if you feed people lots of meat, fish, poultry, eggs, and then switch them to a diet about the same amount of fat, but instead bread, fruit, vegetables, and sugary junk, all their testosterone levels go up. But even more importantly, all their cortisol levels go down. Cortisol is a stress hormone produced by our adrenal glands. Having low stress hormone levels is a good thing, because high cortisol levels may strongly predict cardiovascular death in men and women, both with and without pre-existing cardiovascular disease. In fact, this may help explain death from a broken heart, the heightened heart attack and stroke risk in the immediate weeks following losing a spouse. The higher cortisol levels, days, months, or even years after losing someone you love, may increase cardiac risk and reduce immune function. And you'll note that rise in stress hormone levels losing a spouse, a bump of about 50 points, is less than the bump you may get eating a high meat diet. Cortisol may also help explain why those who are depressed tend to put on abdominal fat. The reason obesity around the middle is associated with elevated cortisol secretion may be that abdominal fat kind of sucks it up. And so the accumulation of fat around our internal organs may be an adaptation by which our body deals with excess stress. These spikes in stress hormone levels every time we eat a lot of meat may not just affect our health, but that of our children. Substantial evidence now suggests that high protein diets during pregnancy has adverse effects on the fetus. For example, back in the 60s, an experiment was performed on pregnant women in Motherwell, Scotland, in which they were told to eat a high meat diet in hopes of preventing preeclampsia, a disease of pregnancy. It didn't work. In fact, the lowest preeclampsia rates I've ever seen were among women eating strictly plant-based diets, only one case out of 775 pregnancies. Preeclampsia normally strikes about 5% of pregnancy. So there should have been dozens of cases suggesting a plant-based diet could alleviate most, if not all, of the signs and symptoms of this potentially serious condition. But what did happen when pregnant women went from eating about one portion of meat a day to like two portions of meat every day? Mothers who ate more meat and fewer vegetables during pregnancy gave birth to children who grew up to have higher blood pressure. One explanation for the adverse effects of high meat and fish consumption is that this may have increased maternal cortisol concentrations, which in turn affected the developing fetus, resetting his or her stress hormone thermostat to a higher level. But you don't know until you put it to the test, and indeed researchers found higher blood cortisol levels in both the sons and daughters of women who had reported higher meat and fish consumption, about a 5% increase for every daily meat serving. Such diets may present a metabolic stress to the mother and kind of reprogram the adrenal access of their children, leading to lifelong hypercordazolemia, elevated levels of stress hormones in the blood. This may help explain why every daily portion of meat during late pregnancy may lead to a 1% greater fat mass in their children by the time they reach adolescence. So this could increase the risk of their children becoming obese later in life, and so have important public health implications in terms of prevention of obesity. Now, if they're already born, you may be able to bring down their stress hormone levels with similar dietary changes. But this is just baseline stress hormone levels. Do children of mothers who ate more meat during pregnancy also have exaggerated responses to life stressors? Researchers put them through a stressful challenge, public speaking, mental arithmetic, and measured their cortisol responses. If their moms ate less than two servings of meat and fish a day while she was carrying them, they got little shots of stress hormones from their adrenal glands. But those whose moms ate more really got stressed out, and those whose moms ate the most, 17 or more servings a week, that's more than two servings of meat a day, appeared to really be quaking in their boots. So in a way, you are what your mother ate.