Intermittent fasting is often marketed like a “shortcut” to lose weight fast. But in a Brello webinar on sustainable weight management, Dr. Stephanie Chan (a pharmacist and mom of two) emphasized a more realistic approach: build habits you can repeat, protect your energy, and avoid strategies that turn food into stress.9
This is for educational and informational purposes only and this does not constitute medical advice.
How does intermittent fasting work for body weight and metabolic health?
Intermittent fasting refers to planned fasting periods and planned eating times—a structured way of spacing food intake without labeling it as “starving.”1 In the webinar, Chan described intermittent fasting as alternating periods of eating and fasting, noting that we already do a basic version of this overnight.9
Some people use intermittent fasting for weight loss, but Chan repeatedly framed it as a tool—not a rule—and not something you “have to” do every day.9
The “fridge vs. freezer” analogy (metabolic switch, simplified)
Chan explained intermittent fasting using a kitchen analogy:
- The fridge (glycogen): short-term energy storage
- The freezer (fat stores): longer-term energy storage
Her point: when eating is constant, the “fridge stays stocked,” and it may be harder to tap into stored fuel.9 Researchers have also described a similar concept as a “metabolic switch,” where longer gaps between meals can shift fuel use toward stored energy in some contexts.2
Intermittent fasting schedule: choosing an eating window that’s realistic
A common approach is time-restricted eating, where you eat within a set eating window each day.1
The 16:8 method (the most common starting point)
One popular intermittent fasting plan is 16:8:
- Example: stop eating at 8:00 PM
- Break your fast at 12:00 PM the next day
That creates an 8-hour eating window.1,9
Other variations you may hear about
You may also hear about alternate day fasting or modified versions (lower-intake days rather than full fasting).3 Research comparing intermittent approaches vs continuous restriction suggests outcomes can vary widely by the person, the plan, and what happens inside the eating window.3,4
Key caution from the webinar: a shorter eating window shouldn’t turn into chronic under-fueling.9 Chan noted that consistently eating very low calories can backfire over time because the body adapts—and “sustainable” usually means avoiding extremes.9
Healthy eating still matters: the Plate Method foundation
In the webinar, Chan started with fundamentals: protein, healthy fats, and fiber-rich carbohydrates, and she cautioned against demonizing or eliminating an entire macronutrient long-term.9
A simple, repeatable baseline is the Plate Method:
- 50% vegetables
- 25% lean protein (roughly palm-sized as a starting visual)
- 25% fiber-rich carbs (quinoa, beans, sweet potatoes)
- Add healthy fats (olive oil, avocado, nuts) for satisfaction9
If an eating window becomes “only one meal,” some people struggle to meet protein, fiber, and overall needs—and may see rebound hunger later.9
What does the evidence say about intermittent fasting for weight loss?
A careful way to summarize the research:
- In some randomized trials, people lose weight with intermittent fasting patterns—often because eating windows can reduce total daily intake for some participants.4
- Across systematic reviews and meta-analyses, results vary by fasting pattern, adherence, diet quality, activity, sleep, and baseline metabolic factors.3
Researchers often track markers such as blood glucose, insulin sensitivity, blood pressure, and other cardiometabolic risk factors.3,4
Safety first: stress, thyroid, eating disorders, and blood sugar sensitivity
Chan emphasized that fasting can act like a stressor in the body.9 For some people that’s tolerable; for others, it can worsen sleep, mood, or eating patterns.
Proceed with caution and consider discussing plans with a healthcare professional if you have:
- high stress or poor sleep
- thyroid conditions
- a history of disordered eating
- diabetes or tight blood sugar management needs9
Stress and cortisol
Chronic stress can affect appetite patterns and weight regulation.5 In the webinar, Chan noted that adding fasting on top of intense baseline stress may backfire for some people over time.9
Thyroid sensitivity
Chan described the thyroid as sensitive to prolonged low energy intake and extreme restriction—another reason she framed fasting as a tool rather than a strict daily rule for everyone.9
Eating disorder history
If fasting triggers obsessive thoughts, guilt, or binge–restrict cycles, it may not be a safe tool.9 A structured, supportive eating pattern is often a better starting point.
How to break a fast in a blood-sugar-friendly way
In the webinar Q&A, Chan recommended breaking a longer fast with a balanced, protein-forward meal rather than a high-sugar breakfast.9 That aligns with general guidance aimed at minimizing post-meal spikes.6
A simple break-fast formula:
- Lean protein first (eggs, Greek yogurt, chicken, tofu)
- Add healthy fats (avocado, olive oil, nuts)
- Add fiber-rich carbs if desired (berries, oats, beans)9
Intermittent fasting and long-term sustainability: sleep, muscle, and consistency
Sleep and stress regulation can influence hunger cues and cravings.7 In the webinar, Chan encouraged paying attention to patterns after poor sleep (snack cravings, drive-thru choices) and treating sleep as a core part of metabolic health—not an afterthought.9
Muscle also matters for long-term weight management. Resistance training supports lean mass, which is tied to healthier metabolic function over time.8
Chan’s bottom line was practical: intermittent fasting benefits tend to come from consistency, not perfection—and many people do better with flexible schedules they can repeat (for example, weekdays only).9
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Final Thoughts
Intermittent fasting can be a useful tool for sustainable weight loss, but it works best when the foundation is strong: balanced meals, enough energy intake, hydration, sleep, stress regulation, and movement you can maintain. In the webinar, Dr. Stephanie Chan emphasized starting with a realistic schedule, avoiding extreme restriction, and paying attention to how your body responds over time. If fasting improves your routine, it may be worth continuing. If it disrupts sleep, mood, or eating patterns, it may need adjusting—or skipping.
Frequently Asked Questions
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Can I have coffee while fasting?
Many people do fine with black coffee or unsweetened tea during a fasting period.9 Add-ins and sweeteners can affect appetite, cravings, and goals differently for different people, so it may help to notice how you feel.9
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I work 12-hour shifts. How does intermittent fasting work with my schedule?
In the webinar Q&A, Chan suggested using long shifts as a natural “busy window,” then planning for one solid nutrient-dense meal and a protein-forward second meal when possible so intake doesn’t drop too low.9
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Why do I crave sugar in the evening?
Chan noted that cravings can show up when earlier meals are too low in protein or overall intake—especially if blood sugar dips and your body looks for quick energy.9 A higher-protein dinner with healthy fats may help some people feel steadier.9
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Is intermittent fasting safe for people with diabetes or blood sugar issues?
Chan said fasting can affect blood sugar and insulin needs, especially for people using insulin or needing tight control.9 If you manage diabetes or take glucose-lowering medications, it’s worth discussing changes with a healthcare professional.9
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What’s the most beginner-friendly fasting schedule?
Chan recommended starting slow and letting the body acclimate (for example, extending the overnight fast gradually rather than jumping into long fasts).9 Many people begin with a 12-hour overnight fast and adjust from there.9
