Chronically elevated cortisol levels increase blood sugar levels, which may contribute to insulin resistance.
Elevated cortisol also contributes to weight gain by inducing stress-related overeating. (Remember this from the last chapter?) Cortisol stimulates the drive to eat supernormally stimulating, nutrient-poor, carbohydrate-dense foods, which may reduce your stress … but increases your girth.
Elevated cortisol levels preferentially direct body fat to the abdominal region (instead of, say, the buttocks or thighs). Excessive abdominal fat (also called central obesity) is part of metabolic syndrome, a collection of highly correlated symptoms: obesity, high blood pressure, insulin resistance/hyperinsulinemia, hyperglycemia, elevated triglycerides, and low HDL (“good”) cholesterol. Increased central obesity is also a direct risk factor for conditions like heart disease, stroke, atherosclerosis, and kidney disease.
Finally, as a weight-gain triple-whammy, elevated cortisol messes with normal thyroid function, leading to a metabolic slowdown that makes it that much easier for you to pack on the pounds.
So if you have an intimate relationship with food-with-no-brakes, and you’re leptin resistant, and you’re insulin resistant, and you’re chronically stressed …
Is it any wonder you can’t lose weight, even on your low-fat, calorie-restricted diet?
We think we can summarize our case right here:
It’s all about hormones.
In real life, these hormones ebb and flow in reaction to various external stimuli: eating, physical activity, sleeping, reacting to stressful situations, and other more subtle influences. There are not enough pages in this book to examine all those influences in detail, but since our book is called It Starts With Food, we are going to explore the effects of eating—the right stuff, the wrong stuff, not enough, and too much—by outlining a few real-life scenarios. These examples will show you why it’s vitally important that the foods you eat provoke a healthy hormonal response—and what can happen when they don’t.
Ready?
First, let’s talk about a prototypical good day.
HEALTHY HORMONES: A GOOD DAY
You are relatively lean and have a healthy diet and lifestyle, and good sleep habits. You don’t overconsume highly rewarding, nutrient-poor foods and your hormones are all in a good, healthy balance. For you, nearly every day is a good day.
Around 6 a.m., cortisol levels (which were very low throughout the night) rise dramatically, helping you wake up a half-hour later feeling like one of those “morning people.”
Thanks in part to appropriately low leptin levels, you also wake up hungry. By 7, you’re sitting down to a simple meal—three eggs scrambled with onion, peppers, and spinach, half an avocado, some fresh blueberries, and a cup of coffee.
There’s not a lot of carbohydrate in this meal, so your blood sugar rises modestly. Your pancreas secretes a proportional amount of insulin in response to the rise in blood sugar, which sends a gentle message to your liver and muscles to take up the circulating blood glucose and store it as glycogen. Because you exercise regularly, there’s some room in your glycogen “tanks,” and because you’re insulin sensitive, the glucose, amino acids, and fats are efficiently transported into cells to start doing their respective jobs.
Over the next few hours, your blood glucose gradually declines, which triggers your pancreas to secrete some glucagon. Glucagon tells your liver to release some glucose back into the blood, keeping your blood sugar in a normal, healthy range. This give-and-take balance is constantly monitored and adjusted, helping to keep your energy levels and mental focus consistent throughout the day.
Around noon, your declining blood sugar and rising “hunger hormones” remind you it’s time for lunch. You enjoy a hearty salad (mixed greens, roasted beets, sliced apples, grilled chicken breast, and walnuts) with an olive oil and balsamic dressing. Though you have only 30 minutes for lunch, you relax and enjoy your meal. The digestive and hormonal response to lunch is similar to that of breakfast—a modest, gradual rise in blood sugar, modest insulin response, and a gradual decline in blood sugar over the next few hours. Glucagon continues to allow you to tap into your glycogen and fat stores to keep you on an even keel.
As your afternoon progresses, things start to get crazy at work, and it suddenly looks like this is going to be a long day.
By 5 p.m., your blood sugar has dipped a little too low, which signals cortisol to use glucagon to release some stored energy, keeping blood sugar and energy levels pretty constant. Because you can use dietary fats (and body fat) as primary fuel and your insulin levels aren’t elevated, you are able to access your fat stores to keep your energy up.
You finally arrive home at 6:30. You’re hungry, but not cranky, light-headed, or lethargic. You dig into the stew (grass-fed beef with chunks of carrot, onion, and tomato) that’s been in your slow cooker all day. This nutritious meal triggers the secretion of satiety hormones like leptin and insulin, leaving you full and satisfied after dinner. The moderate insulin response, as well as a glucagon response stimulated by the protein from the beef, ensure stable energy levels over the coming hours.
By 7:30, your cortisol levels are quite low (even though they were temporarily elevated earlier because of your stressful afternoon). Multiple satiety hormones (including leptin) are elevated, which help you remain satisfied after dinner.
At 8, you prepare your lunch for the next day, grab a good book and a cup of herbal tea and start to wind down before you head to bed around 9:30. You fall asleep quickly and sleep well through the night, facilitated by appropriately low cortisol and stable blood sugar levels.
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Does this experience sound like your typical day?
Most likely not, we suspect.
Let’s examine a more common scenario. It starts with the same early morning, but that morning is very different from the one we just described.
NOT SO HEALTHY HORMONES: A BAD DAY
At this point, thanks largely to your eating habits, you’re a few pounds overweight, leptin resistant and somewhat insulin resistant, and your lifestyle and eating habits have disrupted your normal cortisol levels and daily rhythm.
Your alarm goes off at 7 a.m., and again at 7:09, and 7:18, at which point you head straight to the kitchen, ready for that first cup of coffee. Your cortisol levels are abnormally low in the morning (a dysfunctional situation created by an overly stressful life and worsened by unhealthy eating habits), which means you’re not feeling very bright or perky. You grab a low-fat blueberry muffin, a banana, and some orange juice on your way out the door, and stop at your favorite coffee shop for a large soy latte.
Since your breakfast is almost exclusively fast-digesting carbohydrate (and sugar!), it quickly raises your blood sugar and insulin, aggressively driving energy into your liver and muscles. The high levels of blood sugar give you a kick-start, but by 10 a.m. lots of insulin has pulled too much sugar out of your bloodstream—which means you’re now experiencing the crash that often follows a sugar spike when you’re insulin resistant. This stressful blood sugar crash prompts a cortisol response, which uses glucagon to get your blood sugar back to normal. Glucagon breaks down liver glycogen and increases blood sugar, but since you’re metabolically overreliant on glucose for energy, you can’t use fat efficiently for fuel.
Your brain translates these events as, “Need energy now!”—so you have another cup of coffee, plus half a bagel with peanut butter. Since you’re generally sedentary, your liver and muscles are still full. Some of the carbohydrate from the bagel is used for fuel, but the excess fuel is stored (or remains circulating in the bloodstream).
At noon, you grab a small turkey sub (whole-wheat bread, turkey, low-fat cheese, and mustard), a small bag of baked potato chips, and a diet soda from the deli next door. Again, your carb-dense meal drives blood sugar and insulin levels up, and the caffeine in your soda also prompts a cortisol (stress) response, both of which serve to give you a short burst of energy. Even though there is some protein in the turkey, glucagon’s attempt to releasing stored energy is overshadowed by elevated insulin levels, so once again the sugar is used as fuel, while fat is stored and blood (and liver) triglycerides accumulate.
A few hours later, all of that insulin has driven blood sugar levels too low—again—which means that by 3 p.m. you’ve hit the midafternoon trifecta: you’re tired, hungry, and mentally foggy. Luckily, you’ve stashed some healthy snacks for just such occasions and come up with a granola bar and a low-fat strawberry yogurt. Once again, your carbohydrate-rich snack serves to temporarily prop up your energy levels and mostly stave off your hunger.
Work is busy, and you’re totally brain-dead by 4, so you grab a small iced coffee (with skim milk and a teaspoon of sugar) to get you through the rest of the day. The caffeine in the coffee provokes another cortisol response, which increases blood sugar to give you some energy. That works for a while, but by the time you head home at 5:30, you’re stressed, exhausted, and cranky.
You resist the urge to call for pizza delivery and make chicken parmigiana, with low-fat cheese and whole-wheat pasta, and a side salad. To help you deal with the stress of your day, you also have a glass of red wine. Thanks to leptin resistance, you eat more than you really need, feeling stuffed when you finally put down your fork.
Just two hours later, however, you find yourself craving something sweet. You forage for a pint of frozen yogurt in the freezer and settle in front of the television. By 9, half the pint is gone.
You’re exhausted from your day, but because of your blood sugar volatility and caffeine intake (all provoking a stress response), as well as your poor sleep habits, your cortisol is higher than it should be. You can’t seem to wind down, so you stay up until 11:30, watching the news and sending a few emails. You don’t sleep well, tossing and turning for hours, until your alarm blasts you awake again the next morning.
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Thanks to overconsumption, leptin resistance, insulin resistance, weight gain, hunger dysregulation, and energy spikes and slumps, your day wasn’t quite so pleasant.
What happens in the evening is highly indicative of aspects of your hormonal dysfunction. At the end of your day, leptin resistance and elevated cortisol (thanks to your volatile blood sugar levels and regular caffeine “bumps”) promote hunger and sugar cravings even after you’ve eaten a filling dinner, and make it hard for you to go to sleep (and stay asleep). But even though the day we just described wasn’t so great, it wasn’t that bad, right? You still ate pretty “healthy” food, you still feel pretty good overall, and maybe you’re just a few pounds overweight, so things must be OK.
Or maybe not—because the hormonal disruptions are invisible. Due in large part to your diet, they are occurring beneath your radar. You aren’t necessarily aware of their effects today, but that won’t be the case forever. Let’s see how this eating scenario plays out over months or even years.
After all, this is a “typical day” for most of us.
NOT SO HEALTHY HORMONES: THREE YEARS LATER
You’ve gained fifteen (OK, twenty) pounds in the last three years. Your doctor says that your blood pressure is high, and that you also have pre-diabetes. You’re not sure how all of this has happened, because you’re still avoiding junk food and eating low-fat meals and snacks. But you’ve been stuck in the cycle of overconsumption, worsening leptin resistance, worsening insulin resistance, and an even more disrupted cortisol rhythm. Things are Not Good.
After another rotten night’s sleep, the alarm goes off. Thanks in part to your chronic poor-eating habits, cortisol levels are still abnormally low in the morning, making it even harder to drag yourself out of bed. A cup of coffee gets you motivated enough to shower.
Your out-of-whack cortisol keeps you from being hungry for breakfast, but you force yourself to eat a bowl of shredded wheat with skim milk, a piece of whole-wheat toast with margarine, and more artificially-sweetened coffee. You head to work, stopping on the way for a “skinny” caramel macchiato, your treat for the day.
Your high-carb, low-fat, protein-sparse breakfast yields rapid and prolonged elevated blood sugar levels and a disproportionately high insulin response (because you’re still insulin resistant). These high levels of blood sugar and insulin create “silent” damage in the body and increase your risk for a number of lifestyle-related diseases and conditions.
And that’s just breakfast.
By midmorning, your blood sugar has crashed (cue cortisol to tell glucagon you need blood sugar stat!) and you’re raging hungry, so you grab a low-fat blueberry muffin and a juice drink. Once again, large amounts of sugar begets large(r) amounts of insulin, and you jump on the energy-focus-mood-hunger roller coaster and take another ride. Since you’re eating high-carb foods every few hours, your insulin levels stay elevated, so glucagon rarely has the need to ask cells to tap into fat stores for energy—not that you could, since you are so heavily reliant on sugar.
Your lunch (leftover spaghetti-and-meatballs and a glass of skim milk) recreates the same pattern for the third time today—blood sugar spikes and crashes, provoking a cortisol response. By 3 p.m., you’re hungry again. A fig bar and a small iced coffee stave off hunger until you head home.
When you get home, you’re cranky, lethargic, and totally beat, but you still take the time to prepare a healthy dinner (brown rice, a lean steak, some honey-glazed carrots, and a whole-wheat dinner roll). Since your brain is leptin-resistant (and can’t tell that you’re already overweight), you still have room for a fruit salad with yogurt and granola for dessert.
Later in the evening, the serious cravings start. You prowl through the pantry and freezer on autopilot, looking for more fat, salt, and especially sugar. You settle on a pint of specialty ice cream and the rest of a bag of pretzels—both highly processed, supernormally stimulating and nutrient-poor (all of which, as we’ve been trying to tell you, promote overconsumption and worsening leptin resistance and insulin resistance over the long term).
You’re exhausted, but your cortisol levels are abnormally high, so you can’t wind down until after the last late-night talk show—and you’re in for another fitful night of sleep.
The worst part?
It starts all over again tomorrow.
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In this scenario, those “invisible” hormonal disruptions are finally up close and center. Those additional twenty pounds of body fat are immunologically active—and secreting a lot of leptin. Since leptin’s satiety signal isn’t registering in your brain, you chronically overeat—especially food-with-no-brakes, because it tastes so good.
Your less-than-active lifestyle and continuous overreliance on sugar and carb-dense processed foods has kept your blood sugar and insulin levels chronically elevated for years: you’ve progressed well into insulin resistance—diabetes could be right around the corner. You continue to gradually accumulate body fat, glucagon has no opportunity to tell the cells to use fat as fuel, and you’re desperately reliant on sugar for energy.
Thanks in part to cortisol dysregulation, your body stubbornly holds on to your belly fat even when you try to cut calories—making weight loss even harder.