Is 16:8 better than eating a little less every day?
# Intermittent Fasting or Eating Less? What the Research Says
An eight-hour eating window followed by sixteen hours without food. Or just slightly smaller portions every day.
Intermittent fasting has become a popular way to lose weight, but does it actually work better than simply eating less?
What did the researchers look at?
The researchers reviewed clinical trials of intermittent fasting in adults with overweight or obesity. They looked at 2,307 studies and included 26 in their review. Twenty-four of these were randomised trials, meaning people were randomly assigned to different approaches.
The studies lasted anywhere from 3 to 50 weeks and looked at several different types of fasting, including:
* **Time-restricted eating**, such as 16:8, where you eat within an 8–10 hour window. * **Alternate-day fasting**, where a fasting day is followed by a day of normal eating. * **5:2**, where food intake is significantly reduced on two days each week.
The researchers did not combine the results into one overall number. Instead, they looked at the individual studies separately.
What did they find?
The people following intermittent fasting generally lost weight. The studies also found reductions in fat mass and waist circumference, although the results for lean mass were less consistent.
But there's an important part of the research that can easily get lost.
Some of the studies compared intermittent fasting with simply eating fewer calories every day. They found **no significant difference in weight loss between the two approaches**.
In other words, intermittent fasting can work for weight loss, but the evidence does not show that it works better than reducing your overall food intake.
That may sound obvious, but it is an important distinction. According to this systematic review, fasting does not seem to do anything special for weight loss. For some people, eating within a specific window makes it easier to eat less.
So, should you try intermittent fasting?
It really depends on what works for you.
If stopping food after dinner means you no longer snack in front of the television in the evening, an eating window might be useful. If you prefer three regular meals and smaller portions, there is no reason to change that just because fasting is popular.
You still need to think about what you eat, not just when you eat. Getting enough protein, vegetables, fibre and other essential nutrients matters whichever approach you choose.
And fasting isn't suitable for everyone. If you take medication for diabetes or blood pressure, talk to your doctor before making significant changes to when you eat. If you are pregnant, breastfeeding, or have a history of disordered eating, speak to a healthcare professional before trying intermittent fasting.
What are the limitations of the research?
There are a few important ones.
The researchers did not perform a meta-analysis, so the review does not give us one overall figure for how much weight people can expect to lose.
The studies also varied considerably. They used different fasting methods, lasted for different lengths of time, and compared fasting with different diets or levels of calorie restriction.
Of the 24 randomised trials, 16 were considered to have a low risk of bias. The remaining 8 had a moderate or high risk of bias.
Most of the studies were also fairly short. We therefore have less information about what happens when people follow intermittent fasting for years rather than a few months.
And one final point: everyone in these studies had overweight or obesity. The results do not necessarily apply to people who are already at a healthy weight.
The takeaway
If intermittent fasting makes it easier for you to eat less, it can be a useful tool. But nothing in this research suggests you need to fast to lose weight.
You can get similar results by finding a way of eating that naturally keeps your overall intake appropriate for you.
And whichever approach you choose, it can be useful to keep an eye on what is happening beyond the number on the scales. Blood tests can show how markers such as blood sugar and blood fats change over time and give you a broader picture of your health.
**Source:** Manzoor HMI et al., *Effect of Intermittent Fasting on Weight Loss in Overweight and Obese Adults: A Systematic Review of Clinical Trials*, Food Science & Nutrition, 2026. [PubMed](pubmed.ncbi.nlm.nih.gov/42746281)
Reviewed by
Wellth Team
Wellth
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This article is for informational purposes and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider if you have questions about a medical condition. Wellth health reports do not constitute medical diagnosis.