by Dr. Will Cole
It’s a buzzword you can hardly help from hearing these days, especially if you follow the latest wellness trends: Keto. That’s short for ketogenic, or the ketogenic diet, and right now, it’s the hottest new diet in the news and on bookstore shelves. But is it all it’s cracked up to be? Can it really help you lose weight, get stronger, and have a clearer head? And even more to the point, is it true that keto works for men, but is not so good, or even safe for women? Everyone has an opinion, but let’s delve into the real science to answer those questions.
What is a ketogenic diet?
The ketogenic diet has its roots in neurology. It was originally prescribed to patients with seizure disorders and helped control seizures with some success. The diet goes against everything most of us have been taught about nutrition (especially when it comes to dietary fat) because it encourages a high-fat, moderate protein, limited carbohydrate intake. This encourages the body to switch from being a sugar burner to being a fat burner. Once carbs are very low and fat is high, the body soon detects what the available fuel source is and “goes into ketosis,” meaning that it burns ketones (which it makes from fat) rather than glucose (which it makes from carbs). To accomplish this means bringing on the avocado and nut butter and egg yolks and even real butter, and taking grains—even fiber-rich whole grains—off the plate. How can this be a good idea? As it turns out, the ketogenic has quite a few health benefits, including weight loss, and makes the idea that carbs are necessary for fuel seem antiquated.
Understanding the benefits of a high-fat diet.
For the latter part of the 20th century, we were told that fat was a threat to our very existence: It was clogging our arteries, making us gain weight, and eventually leading to heart attacks. In short, fat was bad. However, there are problems with this public health message, as we have now discovered. For instance, the reasons for the message were based more on marketing and food industry special interests than on facts or solid science. Now, more people are starting to challenge this widely held belief, and an increasing amount of research is showing that there may not be a link between high cholesterol and disease after all. In fact, low cholesterol might be a culprit instead, increasing our likelihood of death.
One of the most interesting avenues of research is concluding that fat is a far superior fuel source than glucose. Like a log to a fire, fat is a slow-and-steady, long-lasting, sustainable form of energy, unlike glucose, which acts like a quick spark or a bit of kindling, burning hot but then quickly dying out. Consider the matter from a biological and evolutionary perspective, Babies rely on high-fat breast milk for energy and growth. This is how humans begin their lives, and even when growth ceases, fat can continue to sustain us in a more reliable manner than carbs. A diet that is fat-focused can also enhance brain health, decrease inflammation, and lower blood sugar.
Finding the ideal macronutrient ratio for you.
This may all sound fine in theory, but there is something else to consider: Bio-individuality. Despite the recent popularity of high-fat diets, it’s important to remember that every person’s biochemistry is different. A ketogenic diet may be right for you…and it may not be. Finding out what works for you is essential for keeping you healthy and fighting fatigue. When it comes to carbohydrates, specifically, individual tolerance can vary greatly, so finding your carb sweet spot can be an important aspect of improving your health and feeling your best.
But are there shortcuts? Can gender be a clue? One big question I often get in my functional medicine clinic is: “Do women need more carbs than men because of their hormonal shifts?” I’m not sure why people believe this, but the current research suggests just the opposite: women may actually need fewer carbohydrates than men and more fat to maintain or reach their ideal body weight and achieve hormonal balance.
Linking carbs and female hormone balance.
To understand why women may benefit even more than men from a ketogenic-style diet, let’s look at how the ratio of macronutrients in the diet influences female hormones. Research has linked a low-fat diet to a decrease in “good” HDL cholesterol (you want this to be high), an increase in triglycerides (you want these to be low), and a 25 percent decrease in estrogen levels (no bueno for most women!). Low estrogen levels in women can lead to brain fog, depression, hot flashes, night sweats, fatigue, and vaginal dryness. Eat more fat, and you can maintain your estrogen levels more effectively and keep them steadier.
What about estrogen dominance, or the condition of having too much estrogen? (This can happen due to early perimenopausal changes and for other reasons, such as exposure to endocrine-disrupting environmental chemicals.) This can cause its own set of health problems, such as weight gain, mood swings, headaches, insomnia, breast tenderness, and heavy menstrual bleeding. Again, this is when bio-individuality comes into play. Finding the optimal ratio of macronutrients for you and your body can help you keep your hormone levels in check. A high-fat diet may help, or it could make matters worse, especially temporarily, until estrogen levels even out again. An experienced health professional can help guide you and help you to determine when estrogen levels are back to normal or dropping too low. (I recommend getting a full blood and salivary female hormone panel with estrogen isomers to figure out your baseline).
Determining the best fuel for the female body.
Although individuals vary, overall, the historical notion that women need more carbs than men has turned out to be wrong. More recent research has demonstrated the female body’s natural preference for fat as fuel. A study that compared fuel metabolism in men and women found that during exercise, women derived more energy from fat oxidation, whereas men derived more energy from carbohydrate oxidation. Even when at rest, women utilized fats more than men. This suggests that some women, especially those with high activity levels and normal or dropping estrogen, may require more fat than carbs to sustain their energy.
Additionally, researchers found that when estradiol, a form of estrogen that peaks during ovulation, was given to rats, their lipid use during exercise increased drastically, suggesting that high estrogen may also benefit from a high fat diet, depending on the individual. It appears that gender may play a role in fuel source preference, and some women may favor fat over carbohydrates, but experiment to see what works for you.
As of now there are not enough studies to show that women always require more carbs or fat than men do. There is no cookie cutter solution. However, what we know now leans towards the notion that women really may need more fat. While these factors are important to consider, your ideal macronutrient ratio has less to do with gender than it does with your body’s particular needs. Overall, your age, level of activity, and health conditions play a larger role in what your body requires than whether you are a woman or a man.
To get the real story, assess your bio-individuality more completely, and determine your ideal macronutrient rations, a functional medicine practitioner can work with you to run diagnostic labs and create a plan that can help you reach your particular health goals.
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