I came across an article at NBC news last week that really excited me. I have always known that moving more rather than less is good for us, more or less. I also know that it is fairly ingrained wisdom in the paleosphere that moving frequently at a slow pace is one of the best forms of exercise, and with good reason.
Walking is one of the best correlates with longevity, for example. That’s pretty powerful.
It also makes a fair bit of sense that our ancestors kept moving fairly constantly.
But what exactly does walking do for us? What is the reason walking works so well?
Turns out, according to Dr. James Levine, a man NBC calls an obesity expert, our metabolisms are analogous to fires that require stoking. Even an hour or two of hardcore cardio cannot “undo the damage done by sitting all day,” he says. The more we sit at rest, the more and more our metabolisms slow. Evolutionarily, this just makes sense. Our bodies burn fewer calories when at rest, and as they detect less and less of a need to burn more, they sink further and further into metabolic sluggishness. This results not just in decreased metabolic rates, but also in lethargy. This is tied to why most people who use standing desks report increased alertness throughout the day. Their bodies have not shut off the way they might otherwise.
“A few years ago, I would have actually said to you, you know, the person who’s doing that session at the gym once a day is doing everything they need to do.” says Levine. ”But the data that are now coming up suggests that’s not the case.” “Being sedentary for nine hours a day at the office is bad for your health whether you go home and watch television afterwards or hit the gym. It is bad whether you are morbidly obese or marathon-runner thin. It appears that what is critical and maybe even more important than going to the gym, is breaking up that sitting time.”
Levine conducted experiments on the matter in 1999. From what I can gather from the NBC article, Levine tracked energy output and metabolism with an EKG which monitored movement and exertion. The results demonstrate how powerful it is to be constant motion, as opposed to trying to squeeze in all of your “calorie burn” at one point during the day.
“People who are lean, even who don’t go to the gym, move about two and a quarter hours a day more than people with obesity, “ Levine learned. “ This seems to indicate that the strongest indicator of leanness is constant movement, not how often you go to the gym. I have been trying to think of some hidden variables that may be clouding the accuracy of this correlation / causation, but I cannot really think of any. Perhaps it is that lean people feel more able to get up and move because their bodies are less heavy, or perhaps they feel more confident about moving, or just enjoy moving more because it feels better in a lean than in an obese body. These are all possible reasons the data might be off, but I find the statistics still as thought-provoking and compelling as before. The scientific data is compelling, too:
The body’s metabolic engines go to sleep, says Levine. In doing so, “the muscles stop moving all together and the heart slows. Then, the body’s calorie-burning rate plummets to about one calorie per minute — a third of what it would be if you were walking. Insulin effectiveness drops and the risk of developing Type 2 diabetes rises. Fat and cholesterol levels rise too.”
This idea also plays out in fidgeting. We’ve known for a while now that people who fidget are leaner than those who don’t. The impulse to fidget may incite people to get up and move, or it’s also possible that the fidgeting itself is a signal of a higher running metabolism. In my person experience, the more I walk, the more I fidget. It seems to me as though my body tries to maintain being “amped” up the more and more “amping” (with gentle movement) I do. These days, I can hardly stand sitting down. It just feels wrong.
If I do sit down, I make sure I get up once and hour and get to move around somehow. I often go to three hour long seminars, and I can feel my body slowing down more and more the whole time. So the “get up and go to the bathroom” solution works. It’s also okay to rest like this from time to time, so long as I know I can get moving another time. I have become an addict to walking to the university. I used to bike, which was more time efficient, but I’ve just got the need to kick my legs for longer and longer all of the time now. When I cannot do these things, I make sure I stand.
And to be clear: I do not do any of this because I am making myself do it. It is just what feels natural now that I’ve integrated more and more gentle movement into my life.
So my personal experience lines up with Levine’s research. My hunger drives are more in tune, my circadian rhythm just feels a bit better, and my energy is far more stable the more I walk. My quads are bigger, my waist slimmer. I exercise in sprint form from time to time, and when I feel like it, and I absolutely advocate that you do the same if it feels good for you. But it’s not the focus of my physical fitness anymore.
But what is your experience? Are you a stander? A walker? A stairs-taker? What does it do for you?
The murky waters of weight status: can you be overweight and healthy? A guest post at Paleo Parents.
Matt and Stacy, the two authors over at Paleo Parents, have graciously invited me to write a blog post at their site. Because the topic of weight loss, and especially from obesity, is so near and dear to their and their readers hearts, I thought it fitting to write about fitting weight status properly into our visions of health.
And two brief excerpts, here:
In July 2012, I wrote a guest post at the Whole 9 blog titled: “How Perfect is the Perfect Body?” The answer, fairly definitively, was “that depends.”
This is because a stereotypically ideal body does not in fact indicate anything definitive about the individual’s health. It is entirely possible to be a lithe, shiny machine of a human being, but still have some sort of internal metabolic disaster. It is also possible to be overweight and to have a healthy internal environment.
There are three primary phenomena that make this possible: first, many health markers other than weight status are crucial for lifelong health. Secondly, the conditions for women are a bit complex: having more fat can be healthier (within normal ranges), and fat loss can be less easy because of hormonal set-points. And finally, a person’s health status can never be truly understood without the context of her history.
Each human being is constructed out of two things: a genetic blueprint and environmental triggers. Unfortunately for us in today’s world, both of those factors can be easily and powerfully deranged.
The vast majority of children in America today are raised on processed, sugary, toxin-filled foods. This puts these people at an immediate disadvantage. No matter what sort of genes they are born with, the ways in which they treat themselves (and so often at no fault of their own) can permanently damage their health.
Consumption of trans fats, for example, has been linked to a long-term reduction in the ability to burn fat.
And seriously restricting calories has been shown to permanently increase the number of fat cells and the rate of fat storage in dieters.
I have been receiving a fair number of e-mails and messages about the Gender Differences in Fat Deposition post over at Mark Sisson’s site. Can I throw my hands up and say “ah ha! We did it! The giants are talking about sex differences. Now I can retire and move on to different projects”? Yeah, maybe a little bit. But I won’t. I’ve become too addicted to this community and work. Which, of course, needs all of the advocates and passion we can throw at it.
Anyway, briefly. I addressed the physiology of women’s weight loss in two posts: The Physiology of Women’s Weight Loss Part I: Estrogen, and The Physiology of Women’s Weight Loss Part II: Appetite and Weight Regulation. I go into a fair bit more depth on both of those topics than Mark does, though he also points out a few great differences:
Women burn fat differently than men. Upper body fat goes first, while lower body fat tends to stay put. Except during pregnancy and lactation, when the lower body begins to give up lower fat stores far more readily. Interestingly (and not by coincidence), women tend to preferentially store the long chain omega-3 fatty acid DHA – the one that’s so important to the baby’s development during and pregnancy – in their thighs.
Women are better at burning fat in response to exercise. During endurance exercise, they exhibit lower respiratory exchange ratios than men, which indicates more fat burning and less carb burning.
Women are better at converting ALA into DHA, and they also tend to have more DHA and AA circulating throughout their serum than men, who have more saturated and monounsaturated fat.
These differences in fat metabolism aren’t seen in isolated muscle cells of men and women, which isn’t really surprising. We’re made with the same basic building blocks; we just run on different software. The differences are systemic and hormonal.
Mark also remarks in his post, much like I did in my estrogen post, that women tend to store fat around the hips buttocks and thighs, and this has been shown time and time again to be healthier than the typical male pattern of abdominal fat deposition. This is well known in the literature and encouraging for curvy women everywhere.
I have, however, been getting a lot of questions about fat deposition in the abdomen. When and why do women still store fat in their abdomens, even though they traditionally have more subcutaneous fat than men?
1) Women store fat in the abdomen during menopause.
Women store fat in their abdomens during menopause fairly frequently. This is because estrogen levels are dropping sharply. Many women supplement with bio-identical hormones, in fact, and see their weight gain / weight shift minimize. Another great way to mitigate this problem is to eat a diet consisting of whole foods, which will minimize insulin spiking that can also contribute to abdominal fat gain, and which will also keep hormone levels fairly well-balanced.
Menopausal women may also want to play around with soy if they are experiencing dramatic menopause symptoms. Please proceed with caution in that case, however. I wrote about how complicated soy is here.
2) Women store fat in the abdomen when they are stressed out.
Cortisol drives abdominal fat deposition. This comes from stress as well as from any loss of sleep quality that may have occurred as a result of stress.
Cortisol and insulin tend to run together, as well, which means that this point and the following point can be difficult to untangle.
3) Women store fat in the abdomen when they are insulin resistant.
Insulin resistant women experience more abdominal fat deposition than those who are insulin sensitive. Moreover, a woman at any single BMI can be insulin resistant, which means that thin women can have IR problems still and deposit fat in their abdomens. The results from one study are particularly striking:
“ We found a strong negative relationship between central abdominal fat and whole-body insulin sensitivity, and nonoxidative glucose disposal, independent of total adiposity, family history of NIDDM, and past gestational diabetes. There was a large variation in insulin sensitivity, with a similar variation in central fat, even in those whose BMI was <25 kg/m2.”
IE: Insulin sensitivity in both overweight and normal weight women drives abdominal fat deposition.
4) Women store fat in the abdomen when they are particularly genetically primed to.
Some women naturally have more fat in their abdomens than other women do– that’s just how genetic rolls the dice. It’s okay, it really is. It does not mean you are unhealthy. Only blood tests might reveal that. Each woman has a different shape particular to her genetics and her history.
Have experiences with different kinds of fat? Fed up with hefty ab fat but non-existent ass-fat like Elissa? Have a hard time loving your stomach even though you totally should? Let me hear it in the comments!Read More
We often conflate the perfect body with perfect health, but that is a flawed concept. The truth is that a fit body provides merely the assumption that an individual has good physical health. What is her fasting insulin? His C-reactive protein? Her triglycerides? These three markers are perhaps the most important indicators of health, with a wide variety of metabolic indicators, hormones, and micronutrient levels all playing important roles. These are the first things we should think of when we want to evaluate physical health—not appearance.
Thank you, Whole9, for kicking ass in this particular advocacy, as in all things.Read More
Many people liked my post on the Happiest, Healthiest, Easiest Weight Loss in the World. The idea is simple: restore proper hormone function by nourishing the body and eliminating food toxins. This type of weight loss is happy because there’s no psychological damage, and body image issues take a back seat when health is prioritized. It’s healthy, because it’s about nourishment first and foremost. And it’s easy because there are no hard-lined restrictive efforts.
I don’t believe that healthy weight loss is ever achieved in the typical brain-body warfare model. Instead, it is only ever achieved when a woman works in partnership with her body’s natural hormone system. If she is good to it, it will be good to her. Easy Peasy.*
Yet this kind of weight loss– this happy, healthy, easy weight loss– is actually for the modern woman enormously challenging. Here’s why:
It requires acceptance.
Perhaps I should have been more upfront about this in the first place. This may in fact be the easiest way to lose weight in the world,* but only if it is done with love, and with forgiveness, and with a refusal to adhere to body image norms. Three things with which women struggle fiercely.
This weight loss will never occur beyond a certain point. It moves a woman down towards a healthy weight, but then it stops, peacefully and joyfully thrumming along at that weight. This weight is not 17 percent body fat. I advise (delicately) anyone fantasizing about that to get over it as soon as possible. No one on this weight loss plan will end up healthfully looking like Cameron Diaz. If a woman were going to be one of those sticky types, she would have always been one of those sticky types. Nor will anyone necessarily be a rippling, chiseled woman. If anyone were going to look like Jilian Michaels, she would have also been birthed on the fiery precipice of hell.
Everyone wants to be thinner. (Almost). According to society, and even according to paleosphere standards, super thin and ripped is hot. Many women in the 20-25 percent body fat range are trying to lose weight with zero real health justification. Zero. What they are instead looking for is to meet the social standard. They may think that meeting this standard is going to make them healthier, or they may make excuses for or justify their weight loss efforts by pretending it will make them healthier, but the fact is that the weight loss endeavor is completely unjustified.
And, in many cases, downright harmful.
Which brings us back to why this kind of weight loss is hard:
In order to be healthy, we have to accept ourselves.
We have to prioritize our health. We may of course lose weight for health benefits, but not for any other reasons. This notion is an indomitable monster for many women (and men) in today’s world. It goes against years worth of programming, and it goes against social pressures and against personal perfectionism and against every desire so many women have ever had to be attractive and loved. Because we have to face it: our desires to be attractive are desires to be loved. So much of the battle we are fighting for holistic health in our brains and in our hearts occurs on this precipice, this edge of love. How can we be loved without being stereotypically beautiful? It sounds ridiculous, but it also is insidiously and powerfully in the subconsciousnesses of all of us.
My proposed method of weight loss is hard because it demands of us that we kick our needs for social validation under the bus. It demands that we take a stand for our natural bodies and our natural needs. It demands that we stand up, that we hug ourselves, and that we tear all of our Shape magazines and gym memberships to shreds. More than anything, it demands that we say “fuck off” to social norms, and that in doing so we ignite in us the power and confidence to accept the love everyone in our lives is showering on us even when we ourselves are uncertain of what we are doing. We need to love ourselves, and to accept love, and to stand with our natural bodies, and to be unapologetic and refusing, and to lead by empowered example after empowered example.
It is not easy to lose weight. Physically, as a woman, fat is valuable, and the body fights to hang onto it tooth and nail. But it is easiest if done with (that albeit hard-won) acceptance and with love and with care. It is healthy if done with acceptance and with love and with care. And it is happy if done with acceptance and with love and with care. Restriction may work in the short term, but it is not healthy in all of these ways, and it may end up backfiring in the long-term. The only way to healthfully lose weight is to do so in loving, proud partnership.
This kind of weight loss–the healthy kind of weight loss–takes not the strength of a physical endeavor, nor the strength of restrictive willpower, but instead the Herculean strength of indomitable spirit, pride, and love.
*Though of course not. Hormones are far more complicated. It’s a bare-boned fact that fat is an endocrine hormone and women’s endocrine systems can be disrupted by changing the volume of fat cells in her body. It is also a fact that many women’s metabolism’s have been damaged by modern foods and toxins. And it is a fact that women’s body have been damaged by diets and exercise. No, it’s not always puppy dogs and candy canes, the land of women’s weight loss, but it can be done, and hormones really can be readjusted to help a woman reach a healthy and fit place with time, care, and love.
**Or not. Ever have a tapeworm?
The question I most often get asked when I tell people about my work in evolutionary nutrition is: why should I trust you? Why should I trust it? Why is this better than any of the other diet options out there?
Oh. Let me tell you.
The world is full of ways in which people, especially women, are supposed to lose weight. There are low-fat diets, low-carbohydrate diets, Lean Cuisine diets, Jenny Craig diets, Weight Watchers diets, juice-cleanse diets, vegetarian diets, vegan diets, slow-carb diets, high-carb diets, blood-type diets, food-combination diets, high-protein diets, USDA-recommended diets, grapefruit diets, low-GI diets, Mediterranean diets, Skinny Bitch diets, Gwenyth Paltrow diets…
Low calorie, high-exercise diets.
Some of these diets more than others are guilty of encouraging restriction. But guilty they all are.
And modern America in general. What lies behind each of these diets is a certain mindset in which expending more energy and eating less is going to make everyone skinny. It isn’t the particularity of each diet that makes it restrictive, but rather the modern mentality that women need to be thin, and the way to achieve this thinness is to eat less and to exercise more. Period.
First, this is wrong. It’s scientifically wrong. Study after study after study shows that the more someone exercises, the hungrier she is, and the more she eats. ”Yes,” you might assert, “But what if she has enough willpower to stop herself from eating more?”
She may in fact have this kind of willpower. I did. I do. But scientifically, that doesn’t matter. The body has a strong homeostatic mechanism. Bodies, based on the foods they are ingesting and the health of their biochemistry, have set points. If a woman is consuming fewer calories than she is expending, her body down-regulates the speed of her metabolism to match that caloric intake, rather than maintaining the original metabolic speed and burning more calories. This is a fact. This isn’t to say that burning those calories is impossible. But it is damn difficult. If a woman’s body is detecting starvation in any way, it’s going to fight tooth and nail to hang onto that fat.
For this reason, caloric restriction is a flawed concept. It does not work. Sometimes people with enormous willpower can do it, but it’s a leviathan of an effort to maintain, and often comes at a price.
This price is the second reason the world needs an Evolution Revolution.
High levels of exercise put wear and tear on a body. Contemporary America is hyper-exercised. Yes, exercise is important. Yes, exercise helps build brain power and memory. Yes, exercise maintains cardio fitness and can promote longevity. But within reason. There is almost no reason in today’s ideas about exercise. When I lost weight, I was putting in sometimes fourteen workouts each week, many of them sprint workouts, and the rest weight-lifting. The world was in awe of me. Few people told me I was killing myself. Instead, people congratulated me and looked at my thinning thighs with envy and reverence. They thought I was a hard-ass, a paragon of Shape magazine excellence, and said breathless things like “If you want an athlete, look at Stef.”
And I did sort of kick ass in the gym. I became a better mid-distance runner than athletes on my college track team. But this work was a) giving me incredible knee pain, b) inflaming my system in general and ramping up inflammatory markers such as C-reactive protein, c) shooting my cortisol and adrenaline levels through the roof, which stressed me out and hurt my sleep, and d) keeping my body in constant starvation mode. I was inflamed, and I was hungry all of the time. That hunger felt unpleasant, and it also upregulated my body’s natural responses to starvation.
So exercise is one way to convince a body it is starving. Another way is with caloric restriction. This is such bad news for a woman’s health, I’d put it right up there in terms of madness with crystal meth and thinking Vin Diesel should still be making movies.
Caloric restriction is bad for a woman’s health because her hormone production shuts down the minute her body’s leptin levels drop below what it’s programmed for. These hormones include testosterone, prolactin, estrogen, and progesterone. They are absolutely crucial for fertility and reproductive health. A woman cannot conceive or maintain babies without them. Moreover, they are crucial for other bodily functions. These include sleep, memory, nutrient transport, libido, bone strength, immune function, energy, the oxidation of fat stores, and happiness. This is not a joke. Hormones are necessary for all of these things. Including happiness. Millions of women today, because of the modern mentality about weight loss and health, scrape by with minimal levels of these vital hormones.
I am not happy about this.
I am not happy about one final aspect of the modern mindset either. It’s related: It is what the mindset does to a woman’s mental health. The reason I say it’s related is that the physiological stress and the hormone issues I described above make the mental health problems harder to bear. But the mental health problems take their root in the very nature of the modern mindset. The modern mindset is about discipline and restriction. And any diet that begs discipline and restriction begs poor mental health.
A restricted diet is a diet that encourages women to think about what they can not have. From this point, women become obsessed with food. They think about what to eat, and when. They worry if they are eating too much. They know that in order to lose weight they have to ignore their hunger signals. They cease listening to their bodies. And then they don’t know what to do, when to eat, how to eat, how much food is appropriate and when. This creates anxiety. Without the normal, healthy partnership between self and body, a woman’s brain is lost, floundering, unhappy, and seeking desperately a kind of ease and contentment about food that will not come. She needs to know what and when to eat, but she cannot listen to her body. She develops a restricted, disciplined, control-based mentality.
Modern America is a factory for eating disorders.
Sixty five per cent of women 25-45 and eight in ten women between the ages of 15 and 30 experience disordered eating, which includes negative relationships both with their bodies and with food.
The insidiousness of the modern mentality with respect to women and mental health does not stop there. Yes, the mindset encourages obsession and anxiety. Yes, it encourages restriction. Yes, it stresses a woman out about how much she should be eating, and whether she should be listening to her hunger signals. Yet perhaps worst of all: it fails. Modern ideas about calorie restriction and weight loss do not work, and for this reason, a woman suffers even more. She beats herself up. ”But I’m supposed to be able to do this! This is how weight loss is done! If I can’t do it, why even bother trying?!” This phenomenon is so common I sometimes take it with me to the punching bag. Women around the world hate themselves for not being able to do something impossible.
Of course diets do not work. They are physiologically stupid. I mean– no, not always. Not necessarily. Some diets that women undertake are extraordinarily well thought-out, and they do work decently. But the general sentiment in America of caloric restriction coupled with high exercise rarely gets people to their desired weight loss goals, and never gets them to optimal health. The modern mindset about weight loss is doomed to fail from the start.
This is why we need an Evolution Revolution for women’s health. We can do it. It’s easy. It really is. More on that in the final post of this series: The Healthiest and Easiest way to Lose Weight in the World.Read More
In the first post I wrote on the physiology of women’s weight loss, I focused on the role estrogen plays in fat stores. I noted at the end of the post that estrogen is involved with sending appetite-regulating signals to the brain. This is an important factor in female weight loss. Men have hormonal feedback that dictates their satiation, too, but their body is less attached to how much fat it has. For a woman, having fat is crucial for pregnancy and childbirth. For this reason, a woman’s body errs on the side of caution with respect to fat stores. When in doubt, it screams “eat!”
What this means is that it is much easier for women to be barraged with physiological demands to eat. These drives are not malicious things, and a woman can never be upset with her body for having them. It’s natural, and it’s necessary for health. Only by accepting our strong biological need for food as physiological fact can we women truly move forward with love, holistic healing, and positive, even pleasurable weight loss.
What follows below is an overview of the mechanisms by which women’s bodies “hang on” to fat stores. This is not to say that the body wants to be overweight. The body actually wants to be a proper, fit, attractive weight. What happens is that normal weight-regulating factors get dysregulated by an inflammatory diet, and prolonged abuse drives a system further and further off-track. The good news is that because a woman’s body wants to be an appropriate weight, once the woman starts treating her body with proper love and nourishment, the pounds naturally slide off.
Fat as a vital organ
Not too long ago, scientists thought that fat cells were simple units of energy storage. Metabolism would grab the energy stored in the fat cells when it needed it, and then the fat cells would continue lying there inert. Metabolism might deposit more energy into them at another time, and then later it would come grab the energy back. Fat cells were considered storage units, and not anything more.
Since 1994 with the discovery of leptin, science has gradually unearthed the surprising notion that fat tissue is not just a storage space but is also an endocrine organ in and of itself. Fat receives signals from hormones; it is actively involved in how much fat gets stored within its own reserves, and how; and it sends out potent signals of its own. These signals are crucial. They tell the brain how much energy is currently being stored in the form of fat. Higher levels of leptin signal to the hypothalamus that an organism does not need to eat anymore. Potent appetite stimulators such as neuropeptide Y and anandamide are inhibited by leptin in the hypothalamus, and the production of alpha-MSH, an appetite suppressant, is encouraged. Though there are dozens of hormones and neurotransmitters involved in signalling appetite to and from the brain, what this demonstrates is that leptin more or less runs the show. More leptin = less eating.
That is, unless the organism is leptin resistant.
Leptin resistance occurs when leptin has flooded a system. In addition to originating in fat stores, leptin levels in the blood rise with food consumption. Leptin 1) spikes after consumption of a large meal, particularly a carbohydrate-heavy meal, since leptin works in tandem with insulin, and 2) it sort of dribbles into the bloodstream if food is eaten in smaller quantities throughout the day. So leptin levels rise whenever the body really thinks it has been well-fed.
Over-secretion of leptin is the primary means by which people dysregulate their leptin signalling, for example, if they eat too many meals without waiting for hunger to return in between them, or if they graze on food all day, or if they have a couple of snacks each day. Basically, leptin resistance develops when normal weight-regulating drives are ignored. This is easy to do in the presence of highly palatable food and drink. Other factors that can throw someone’s leptin signals under a bus are stress, loss of sleep, problems with neurotransmitters, or nutrient deficiencies. Under the influence of these factors, or perhaps several of them in conjunction, it becomes difficult for a woman to hear the leptin signalling in her hypothalamus.
Once people begin ignoring their leptin signals, they get easier and easier to ignore. This is because constantly elevated leptin levels cause leptin receptors to become insensitive to the leptin floating around in the bloodstream. Then, as the body realizes that it’s normal leptin signalling isn’t getting the job done, it incites more eating, more weight gain, and higher leptin levels in hopes that an increased leptin signal will get through. For this reason, obesity is correlated with high leptin levels, even though many obese people complain of constant hunger.
Leptin resistance is a problem for everybody. Both men and women. Without fixing leptin sensitivity problems, it’s very difficult to lose weight, and it’s even more difficult to enact any kind of dietary restriction. But women, who have higher levels of leptin than men (having higher body fat percentages) and who have HPA axes more attuned to energy conservation, are particularly sensitive to fluctuations in leptin levels.
Leptin and menstruation
Achieving a certain leptin level is the primary trigger for menarche (the first incidence of menstruation) Stress, genetics, being exposed to smoking, and not being breast fed are other important factors. So far as researchers can tell, throughout evolutionary history a woman’s period likely started around 15 or 16 years of age. A few studies were conducted in the nineteenth century documenting menarche. In 1850, girls began menstruating at an average age of 17; by 1960 that age decreased to 13 years old. Today in America, approximately ten per cent of girls start to menstruate before 11 years of age, and ninety per cent of all US girls are menstruating by 13.75 years, with a median age of 12.43 years. Both black and latino girls begin menstruating before white girls.
Many suspect that the higher body weights and higher leptin levels are responsible for the change in menarche. A 2011 study found that each 1 kg/m2 increase in childhood BMI can be expected to result in a 6.5 per cent higher risk of menarche before reaching 12 years of age.
Leptin and the reproductive set point
Knowing about puberty and menarche is so important for adult women because a woman’s reproductive functioning for the rest of her life is influenced by the conditions of her early reproductive years. Having started menstruation with a certain leptin concentration in the blood, a woman’s body treats this as a “set point ” of sorts later on. Having had a certain level of leptin, too, influences the young girl’s estrogen and progesterone levels, such that these also become reproductive set points. Therefore, if a woman drops too far below her set leptin or estrogen levels later in life by losing too much weight, her body will do its damndest to get those levels back up. A similar phenomenon happens if she becomes overweight and leptin resistant.
Stimulating appetite in response to low leptin levels
The way a body tries to increase leptin and estrogen concentrations is to increase fat mass. The way to increase fat mass is to increase appetite. This is why leptin is such a potent signal in a woman’s brain. With decreased leptin levels (or leptin insensitivity), appetite-stimulating neurons up-regulate powerfully.
Importantly, more women profess sugar addiction than men. One of the neurons that detects decreasing leptin concentrations in the blood is called Neuropeptide Y. Neuropeptide Y stimulates carbohydrate craving. Women who are experiencing starvation– or at least women who’s hypothalama are detecting lower leptin levels than their bodies think are optimal — experience insidious carbohydrate cravings.
Are women stuck in leptin set points?
No. Not necessarily.
The thing is, it’s complicated. A woman’s body will never “want” to be overweight. Women start menstruating at a certain leptin level and at a certain age, but even if this occurs at a very young age, the leptin is still around the same absolute level that another woman might experience, just many years earlier. So her leptin levels, if higher earlier than optimal, still are not shooting through the roof at menarche.
Moreover, if a young girl is overweight when she starts her period, at that time her body is probably fighting for and signalling a desire to lose weight. It’s just not working because some of the signals have been disturbed by poor diet and lifestyle. This woman’s body’s need for and desire to lose weight will persist for the rest of her life. The hormone and appetite pathways are all still in place. They are just begging to be restored to their normal function. All the woman needs to do is listen, and to nourish her body properly. In this way, it will be her partner in weight loss, rather than her adversary.
Other appetite stimulators
Appetite is stimulated via a few other important pathways. They are not limited to women. For example, an individual’s cravings for certain foods increases as a result of nutrient deficiencies. Fluctuating insulin and blood sugar are important. Stress is important. Social conditioning, negative thought patterns, psychological responses to hardship, and body image issues also powerfully stimulate cravings.
Neurotransmitters as appetite stimulators
Perhaps most significant, however, is the relationship between neurotransmitters and food, specifically for women. When serotonin levels drop, cravings, again, particularly for carbohydrates, increase. Serotonin levels can be disrupted by a vast number of problems. These span from nutrient deficiencies to an omega 6 – omega 3 imbalance to poor sleep to obesity to exercise and to stress. Serotonin levels also fluctuate with the menstrual cycle. A drop in serotonin during the luteal phase (the last two weeks) of the menstrual cycle is thought to be by many the dominant cause of PMS. This would explain why many women experience increased cravings for sweets throughout PMS. These are natural, up to a point. But PMS is an extreme fluctuation, and solving the underlying diet and lifestyle factors causing PMS should also decrease the wild swings in cravings that many women suffer throughout their menstrual cycles.
The role of neurotransmitters in appetite deserves several posts of its own. They are forthcoming. For now, it suffices to note that neural mood regulators are strong links between a woman’s reproductive system and her weight regulation mechanisms. Sub-optimal serotonin levels in particular increase carbohydrate cravings.
All that said…
Women come equipped with a system designed to maintain adequate fat mass. If a woman is overweight, it’s because the normal weight regulators she has in place are not receiving the proper nourishment required for effective signalling. Leptin insensitivity, in the case of an overweight woman, or low leptin levels, in the case of an underweight woman, compel her to eat and to eat and to eat. Estrogen, as I noted in a previous post, is also a significant weight-regulator unique to women. It, too, is disrupted with diet and lifestyle. Therefore, with the restoration of the proper functioning of all of the underlying mechanisms at work in a woman’s body, specifically with leptin and with estrogen levels, a woman’s weight can slide off. More on that in my upcoming post on the easiest, most natural way (paleo diet! decreased stress! self-love!) for women to lose weight.