Intermittent fasting is a topic that comes up a lot. It is widely researched, but also highly controversial. The research is quite conflicted at the moment, so there are a lot of mixed messages out there.
What is Intermittent Fasting?
At its core, intermittent fasting is about eating within a restricted time window. The most common approaches are:
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16:8 fasting: You fast for 16 hours and eat within an 8-hour window, for example from midday to 8pm.
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5:2 fasting: You eat normally for five days and eat very few calories on two days.
Who Could It Help?
Research does agree on one thing. Intermittent fasting can help some people stick to a calorie deficit. In other words, if you naturally eat fewer calories because your eating window is restricted, you might lose weight or body fat.
It is important to be clear. Fasting itself is not inherently better for weight loss. If you need 1500 calories to lose weight, whether you eat those calories over 8 hours or 12 to 15 hours does not make a difference. The benefit only comes if fasting helps you stay under your calorie target.
Who Should Avoid It?
I would not recommend intermittent fasting for anyone who has had a difficult relationship with food. This includes anyone who has experienced disordered eating or has an all or nothing mentality around food.
I also probably would not recommend it for perimenopausal women. Hormones are already under strain and going long periods without food can cause irritability, dizziness or dips in blood sugar. Our bodies and emotions are under enough strain without adding extra stress from fasting.
Why Protein Matters
After the age of 30 we start to lose muscle year on year (if we don’t regularly strength train and eat adequate protein). Spreading protein intake throughout the day can help maintain lean muscle mass. Regularly and consistently missing a protein window because of a long fast could affect this.
The Other Claims
Many people try intermittent fasting for reasons such as improved insulin sensitivity, gut health, or as a type of “cleanse”. The evidence for these claims is conflicted. There is no solid proof that fasting benefits the body in these ways.
Some recent studies are worth noting. A German study published in Science Translational Medicine (2026) found no measurable improvements in metabolic or heart health parameters when participants followed a time‑restricted eating window without reducing their calorie intake: ie fasting is not a magic pill. It only helps with weight loss if it supports a calorie deficit.
Another large study of over 20,000 adults looked at people eating within an eating window of less than eight hours a day and compared them with people eating across a 12 to 16 hour period. This research found that people who limited their eating to less than eight hours were associated with a significantly higher risk of dying from cardiovascular disease over time compared with those eating across a longer window, although the reasons were unclear and more research is needed. Anyone with heart issues or diabetes should speak to a medical professional before trying intermittent fasting.
My Personal View
If you are active and want to maintain consistent energy throughout the day, intermittent fasting might not be the best option. Personally, I prefer to eat regularly to maintain energy, mood and spread protein intake. Hunger, energy dips and irritability can make long fasts difficult, especially if you are busy and active.
At the end of the day, intermittent fasting is highly individual. Some people find it works for them and others do not. It is all about what helps you feel your best and stick to your goals!
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