Intermittent fasting is all the rage right now, for good reasons. Extending your overnight fast – the period of time that you naturally don’t eat because you’re asleep – is pretty easy for most people to do, and it’s one of the fastest ways to stop insulin resistance in its tracks.
Exactly what is insulin resistance?
This is when the insulin receptor sites on your cells shut down and can’t work properly. This is caused by eating too much food that breaks down into glucose (starchy carbs, sugar, and alcohol). Specifically, one or more of these habits are problematic:
- You simply eat more glucose-containing foods than your metabolism can handle at one sitting.
- Most of your glucose intake is from refined foods like things made from flour and sugar, or from sugary or alcoholic beverages.
- You graze all day without significant breaks.
- You eat from the minute you get up until right before you go to bed.
This boils down to too much, too frequent, and too long.
When insulin receptors are shut down, then both insulin and glucose stay elevated in your bloodstream and raise your risk of:
- Turning excess glucose into fat – shown by high triglycerides and high LDL cholesterol.
- An increase of yellow-brown belly (visceral) fat which is different than fat anywhere else in your body. Visceral fat is metabolically active, like an organ. It pumps out inflammatory cytokines – and it’s never a good thing to pump up useless systemic inflammation.
- Excess weight that’s extra hard to get rid of because you’re inflamed. Inflammation from visceral fat blocks weight loss – a catch 22.
- High blood sugar – shown by elevated fasting blood sugar and hemoglobin A1C.
- High blood pressure.
- Type 2 diabetes, heart disease, and stroke.
- For women, elevated androgen (“male”) hormones, polycystic ovarian syndrome, and the gamut of period problems.
Insulin resistance, metabolic syndrome, and prediabetes are different terms for essentially the same condition. According to the CDC in 2015, 38.9% of Americans 18 and older are prediabetic, and at age 65 it’s HALF the population. Americans, as well as other overfed countries, are getting fatter and more diabetic as the years progress. Sadly, this is only predicted to get worse – unless we do something to stop it.
Why intermittent fasting makes sense
24-hour convenience stores, packaged food, and refrigeration allow us unlimited access to food, which may seem like a good thing – except that this easy access to overfeeding is the leading cause of our prediabetes epidemic. The ability to eat virtually anything, at any time, allows us to easily snack for 16 waking hours a day – and that’s if you are an adult who actually gets eight hours of sleep.
Eating over a 16-hour duration means you constantly crank up your blood sugar and insulin 16 hours a day. Your metabolism and insulin receptors wear out without sufficient rest. Simply taking a longer break overnight, by breaking your fast (break-fast) after a 12 or 14 hour rest, allows your metabolism time to rest. During this time, insulin takes a break, and your insulin receptors have time to recover. Just as your muscles need recovery time after exercise, so do your cell’s insulin receptors after a long day of insulin bombardment.
And, during this break, your body naturally uses up the glucose you store in your liver and muscles (called glycogen) and then digs into your fat stores to burn fat for energy. This process is deeply wired into your metabolism, and simply taking a break from eating as our paleolithic ancestors were forced to do, evokes your ability to re-set your metabolism and burn fat stores.
New research backs up intermittent fasting
A new study in Cell Metabolism followed 19 people over 12 weeks, who fasted daily for 14 hours and restricted their window of eating to 10 hours (time-restricted eating or TRE).
The participants were not asked to change their food intake at all, However, there was a reduction of 8.6% caloric intake, likely an organic result of limiting the hours allowed to eat (think no late-night ice cream binges).
The participants in the study were all overweight with signs of metabolic syndrome. The study results were impressive in terms of:
- 3% reduction in weight
- 4% reduction in visceral fat, with lower waist circumference.
- Lower total and LDL cholesterol
- Lower blood pressure
- Hemoglobin A1C (a diabetes marker) lowered
- More restful sleep
- Better energy
The National Institute of Health (NIH) is currently conducting a larger study on the effects of intermittent fasting – pretty exciting.
What is the right amount of time to fast?
If you read about intermittent fasting, you’ll see different lengths of time recommended for fasting. The research study above shows 14 hours. This length of time has evidence behind it. However, there’s also evidence that shows a 12 hour fast is sufficient to get results.
In my clinical experience with women and intermittent fasting, I consistently see 12 hours as sufficient to get results with reversing insulin resistance and achieving weight loss. 12 hour fasts may be especially beneficial if you . . .
Tend to binge eat at night
Time-restricted eating means the kitchen closes after your last meal. This provides a no-thought structure that naturally stops the late-night desserts. Open and closed eating hours can provide a comforting and welcome structure, and it’s so simple.
Failed diet after diet
Diets, in general, have a very low success rate. Food restriction and tracking can make women feel deprived, which leads to rebellion and overeating – this is human nature. Significant calorie restriction (under 1200 kcal per day) can backfire by lowering your metabolic set point so that you gain weight as soon as you stop restricting. This may be you if you feel like you gain weight simply by looking at food.
Experience a high level of stress
For women under chronic stress, I recommend limiting fasting to 12 hours. This is because pushing the fasting time longer will upregulate stress hormones. If stress is already a problem, adding to it can risk dysregulation of the HPAO axis (hypothalamus-pituitary-adrenal-ovarian axis) which can lead to sleep, energy, mood, and female hormone problems.
How to know if you have too much stress to risk fasting for 14 hours? Take this quiz, and if you score “in good health” then go for it! If not, stick to 12 hours.
For most women, fasting for 12 hours is sufficient and safe. Listen to your body signals, or consult your health provider to push it to 14 hours, and you do NOT need to fast 16 hours to get results.
I’d love to hear your thoughts below,