Written and medically reviewed by Naomi Parrella, MD
As a physician, an educator, and a parent, some of my favorite moments are when someone wants to learn more about their body — I love to answer questions! That’s why the Zero team and I have decided to take Member questions from our Zero Live webinars and answer a few here every month. Over time, you will learn how your body works, what might be happening when it’s not doing what you want, and how to get it back on track to do what it is designed to do: repair, heal, and thrive.
Q&A
Q: How exactly does intermittent fasting help me lose weight? Is it by calorie deficit or does it actually change the body’s metabolism?
A: The answer is: both. In fact, the changes in metabolism are what can lead to the caloric deficit.
If you remember from this article or this webinar, insulin (which is triggered by blood sugar, which is triggered by food) plays a large part in building fat deposits; therefore, low insulin is what permits fat burning. Intermittent fasting impacts your metabolism by allowing insulin to lower naturally and thereby boost your fat-burning capabilities.
As your body gets better at burning fat, you’ll also improve your metabolic flexibility which gives you access to your largest fuel source — your fat cells. This means your body has access to “enough” fuel at all times, so it doesn’t need to send you so many hunger signals, and you feel more satisfied eating fewer calories. Additionally, the more fat you burn, the more ketones you produce, and ketones naturally suppress hunger, contributing to the ease of ending up in a calorie deficit. The important distinction here is that this caloric deficit is spontaneous. It’s different from forcing a calorie deficit, which results in your body not having enough fuel for optimal function and repair. With intermittent fasting, you aren’t depriving your body, you’re training it to access all the fuel it needs!
Q: I’ve been fasting for 5–6 months and have lost 30 pounds. I’m at my last 27 pounds to reach my goal, and progress has slowed. What’s going on?
A: Weight loss without medications or surgical intervention is rarely linear. In fact, it usually looks more like a stepladder: lose some weight, then pause (a.k.a. plateau). Then lose some more weight, then pause/plateau again. This pattern repeats over and over, and as you get closer to your goal weight, the pauses can grow longer.
The reason for these longer pauses might have to do with how you gained the weight. As a person gains weight, they naturally hit weight plateaus on the way up, too: They’ll gain weight, then stay at that weight for a time, then gain more weight, then stay at this higher weight for a time, and so on. If you were at a certain weight for a long time in the past on the way “up,” then you may experience that same weight as a stubborn set point on the way down. This is very common! Unfortunately, people often throw in the towel and give up at this point. Don’t!
If you continue your health-promoting behaviors and fasting patterns, while the weight on the scale may not change, you’ll often find that your clothes start feeling looser and you “look like” you are losing weight. This is due to your body composition changing. Your weight may be redistributing, and you may develop more muscle and less fat tissue. This is a fantastic time for your body! It’s “resetting” itself to this new weight, and overwriting your last highest weight. This is how you achieve long-term weight-loss maintenance, so stay in the game!
Q: I fast daily and work out regularly, yet it’s very hard to make progress losing weight. What else can I do?
A: The human body is evolutionarily designed to prefer gaining weight and to only lose weight (with the exception of pregnancy) if it is sick or dying. So start by knowing that you’re not alone. Losing weight is hard!
That said, your history of weight-loss efforts may factor into your current challenges losing weight. The more times your body has experienced a “forced” weight loss — through calorie restriction despite being hungry or with weight-loss medication — and then “learned” how to regain weight, the more challenging it is to lose weight. The human body is smart! So for many people who have a long history of “yo-yo” dieting, the most successful long-term weight-management plan will require a more personalized approach crafted with the help of an obesity-medicine specialist.
Whether or not you have a history of forced weight loss, the most powerful thing you can do is to start tracking and identifying if any of these tips are relevant to you.
Here are a few possibilities that might be hampering your current weight-loss efforts:
- Chronically high cortisol from unrelenting stress and poor sleep interfere with weight loss! To counteract this, spend time with people who recharge you, practice stress-management techniques (like yoga, meditation, and non-sleep deep rest), and improve your sleep by starting your fast at least 2 hours before bed.
- If you’ve been fasting every day for an extended period of time, you might just need a break. Taking one day per week or even one day every couple weeks to eat freely can help boost your calorie intake — which might seem like the opposite of what you should do to lose weight, but which is actually important for maintaining your metabolic rate (which accounts for ~65% of the energy you burn each day!).
- Assuming you haven’t done this already, try moving your workout to within your fasting window. Alternatively, try changing up the workout itself for a different stimulus. If you tend to prioritize cardio, shift the balance towards strength training, or vice versa.
- You might be sitting too much. Structured exercise is great, but your movement throughout the day matters a lot. Can you stand at your desk while working? Call into a meeting on a walk? Taking breaks to do small home-maintenance activities, chores, or yard work is another good option.
- Chronically elevated insulin prevents fat burning, and frequently spiking insulin regularly turns fat burning off. To see whether either of these conditions applies to you, consider trialing a continuous glucose monitor (CGM).
- Some medications interfere with weight loss and may even cause weight gain. If you’re taking any medications regularly, talk with your doctor about which ones might be curtailing your weight-loss efforts and see if there are effective alternatives.
- Finally, certain metabolic and hormonal alterations might be getting in the way of your weight loss. Contact your healthcare provider and ask them to run some labs!
Q: I’ve always been thin, but menopause has me putting on the pounds, even though I am eating less and eating better. What gives?
A: You’re not imagining it — your hormones are causing your body to change. Estrogen in particular, as part of the menstrual cycle, helps your body stay sensitive to insulin, which allows you to burn fat easily. Estrogen also guides your body to distribute fat in a “female pattern,” which is what gives females our curves. When menopause happens, your estrogen drops, leading to increased insulin resistance and resulting in you building fat more easily and burning fat less. (Also, given the lack of estrogen, the fat distributes more like it would on a male, around the waistline.)
Wrap-Up
In sum, changes in hormones lead to changes in insulin, which left unchecked can lead to storing more food as fat. Therefore, what you want to do is find ways to keep your blood sugar, and in turn your insulin, from staying chronically elevated or spiking so you can remain in a fat-burning state. Some ways to do that include fasting; cutting alcohol, sugars, and/or ultra-processed foods from your diet; and walking before or after your meals. Try any or all of these for a month and see what happens! There are plenty of tools to help you — Zero being the most obvious one, but you can also use a CGM to track how your blood sugar (and in turn your insulin) might be responding.
Have a question for us? Be sure to join the next Zero Live!
- Q&A with Dr. P: Recovering after Exercise - August 2, 2024
- Q&A with Dr. P: Exercise While Aging - July 22, 2024
- Q&A with Dr. P: Weight Management Tips & Tricks - June 6, 2024
