Intermittent Fasting
If you've come across intermittent fasting (IF), you may be wondering whether it’s something you should try.
It may have been recommended by a friend or even a healthcare provider, and it’s often associated with a range of health claims. This resource is designed to give you a clear, evidence-based understanding of what intermittent fasting can and cannot do, so you can decide if it’s something you want to experiment with.
What is intermittent fasting?
Intermittent fasting is not a specific diet. It’s simply a way of organising when you eat.
In practice, there are several ways to do this. Many people start with a daily eating window, for example, eating between late morning and evening, and not eating overnight.
There is no single “correct” version. What matters most is whether the structure feels:
- manageable in your day-to-day life
- supportive of your appetite and energy
- realistic to sustain over time
Does It Lead to Weight Loss?
Intermittent fasting can support weight loss for some people. However, research into different weight management approaches shows it is no more effective than other approaches that reduce calorie intake.
In other words, it works when it helps you:
- eat a little less overall
- feel more in control of your eating
- stay consistent over time
For some people, having a defined eating window naturally reduces intake. For others, longer gaps between meals can increase hunger and make eating feel harder to manage.
If this strategy increases hunger or feels restrictive, it may not be the right fit. The table below shows how intermittent fasting compares with a more traditional structured eating pattern.
Intermittent Fasting vs. Structured Eating
| Intermittent Fasting | Structured Eating |
|---|---|
| Often fewer meals in a shorter eating window | Usually 3 meals with or without snacks |
| Can feel simple | Can feel steady and predictable |
| May reduce grazing | Helps regulate hunger across the day |
| May increase hunger for some | Often supports more stable energy |
| Can be harder socially | Often easier to integrate into daily life |
Both approaches can work, particularly when meals are designed to provide a balance of nutrients that provides energy and satiety. The goal is finding a strategy that feels sustainable while supporting your appetite and energy.
How It Feels in Real Life
One of the main reasons people try intermittent fasting is that it simplifies decisions: Fewer meals, clearer boundaries, and defined start/stop points. For some, this creates ease. For others, it can be effortful and feel uncomfortable.
If you experiment with intermittent fasting you might notice:
- Less grazing
- More awareness around meals
Or you might experience:
- Strong hunger earlier in the day
- Lower energy or irritability
- Eating past fullness when breaking the fast
These are not signs of success or failure, but simply useful feedback that allows you to understand how your body responds to this structure.
A flexible approach works best
It’s common to feel like you need to “stick to the window” perfectly. In reality, flexibility tends to lead to better outcomes. For example:
- If you feel very hungry, eating earlier is a helpful adjustment, not a mistake
- If your schedule changes, your eating pattern can change with it
- If something isn’t working, it can be modified rather than abandoned
Breaking your fast early does not have negative health consequences. Intermittent fasting works (when it does) because it helps create a calorie deficit, not because of strict timing rules.
Experimenting with Intermittent Fasting
If you are curious to get first hand evidence whether this approach is right for you, think of intermittent fasting as a short-term experiment, not a long-term commitment.
How to Start
Because there are numerous protocols for intermittent fasting, you can design your own approach.We suggest starting gently to discover what eating window (the amount of hours your fit your meals and snacks into) feels comfortable for you:
- Delay breakfast slightly or
- Finish eating earlier in the evening
Like any other dietary approach, try to focus on meals that include protein, fiber, and healthy fats to leave you feeling satiated and to meet your nutritional needs.
As you are running your intermittent fasting experiment, pay attention to and gather data on:
- Hunger patterns
- Energy and mood
- Your sense of control around food
These signals matter more than following a plan perfectly.
Risks and considerations
Intermittent fasting is not appropriate for everyone.
- Blood sugar medications: Longer gaps between meals can increase the risk of low blood sugar (hypoglycemia). This is why it’s important to speak with your dietitian or prescriber before trying intermittent fasting
- History of disordered eating: Intermittent fasting can increase rigidity around eating and may trigger cycles of restriction and overeating in some individuals.
- Fasting longer than 24 hours: This is not recommended due to risks such as electrolyte imbalance, loss of muscle mass, nutrient deficiencies and adverse health events.
- Hydration: Fasting from food does not mean restricting fluids. Staying hydrated supports energy, concentration, and overall health. If you are thirsty at any time of day - drink!
Intermittent fasting and diabetes
Weight loss plays an important role in improving insulin resistance and blood sugar levels for people living with type 2 diabetes, and in some cases can support remission. Intermittent fasting may help some individuals achieve this by naturally reducing overall calorie intake within a shorter eating window.
Some research suggests that approaches such as eating within an 8-hour window (and fasting for 16 hours) can lead to short-term improvements in blood sugar levels and weight. However, the longer-term effects are still being studied, and responses can vary significantly from person to person.
Because intermittent fasting changes the timing of meals, it can also affect blood sugar levels in ways that may not be safe for everyone, particularly for those taking medications that lower blood glucose. For this reason, it’s important to speak with your dietitian or healthcare provider before trying this approach.
What is right for you?
There is no single best way to eat. The most effective approach is one that:
- Feels sustainable
- Supports your health
- Fits into your daily life
Intermittent fasting is one option. It works well for some people and not for others.
A helpful question to ask yourself is: “Does this way of eating make my day easier or harder?”
Your answer to that question is often the most useful guide!
If you want to experiment with or if you have any further questions about intermittent fasting please reach out to your Constant Health dietitian to learn more.