A major new study published in the BMJ reviewed nearly 100 clinical trials to help answer that question. Here’s a breakdown of what they discovered – and how it might help you figure out what’s right for you.
What Did the Study Look At?
Researchers looked at over 6,500 adults trying different ways to lose weight. These included:
- Alternate-day fasting (ADF): Eat normally one day, then fast (or eat very little) the next
- Time-restricted eating (TRE): Eat only during a set window each day (e.g., between 10am–6pm)
- Whole-day fasting (WDF): Fast for one or more full days each week
- Daily calorie restriction (CER): Reduce how much you eat every day
- No specific diet (ad libitum): Just eat normally without a structured plan
The goal? Compare the effectiveness of these diets in helping people lose weight and improve factors such as cholesterol, blood pressure, and blood sugar levels.
So… Which Diet Worked Best?
The good news? All the structured diets helped people lose more weight than those who weren’t following any plan. Alternate-day fasting (ADF) had slightly better results than traditional daily calorie cutting — people lost about 1–2 kg more, on average, but this wasn’t a huge difference in the bigger picture.
The bad news? The average amount of weight lost was only a few Kg in all the diets studied.
The BIG news? Losing weight is not always the same as gaining health, so studies that focus on kilos over health outcomes and disease prevention or control, should be looked at with caution.
Most diets had similar results when it came to improving things like cholesterol and blood sugar, and again, this was a small impact overall.
What Does This Mean for You?
The main takeaway is simple: There’s no one-size-fits-all diet.
What matters most is finding something that works for you — something that fits your lifestyle and that you’re more likely to stick with.
And if a particular diet strategy is impacting on your quality of life or mental health, changing your approach is fine.
The most effective diet is one that is health-promoting, and you can maintain and adjust, not just for weeks, but for the long haul.
Why Long-Term Support Matters
What this and other studies often gloss over, is eating less is not always eating better. And there are real concerns about the potential impacts on mental and physical health from aggressive diet culture. Another big challenge is sticking with a diet over time. In fact, the study found that fewer than 1 in 4 people were still following strict fasting diets a year later (which might be a good thing in some cases)
That’s why having the right support – whether it’s through your healthcare team, a dietitian, or exploring other treatment options – can make a big difference.
Thinking Beyond Diets: Bariatric Surgery as an Option
If you’ve tried multiple diets and still struggle with your weight or related health problems, it’s worth knowing that metaoblic bariatric surgery (also called weight loss surgery) may be an option for some people.
It’s not for everyone, but for those who meet the medical criteria, it provides long-term health improvement, reduced chance of death (and yes, long-term weight loss as well).
Some health conditions that may improve after metabolic bariatric surgery include:
- Type 2 diabetes
High blood pressure - Sleep apnoea
- Joint pain or mobility problems
If you’re wondering whether surgery might be right for you, the first step is to speak with your GP. They can refer you to an metabolic bariatric surgeon for a full discussion about your options.
And yes, GLP1 medicines too:
Newer obesity management medications (sometimes called GLP1s) can also work, and may be more suitable for people who do not meet the medical criteria for metabolic bariatric surgery. But there are a few key facts to remember:
- They only work (like diets) while you are on them – people who stop the drugs start returning to their original health state (and weight) pretty quickly.
- They have not worked as well in the real world as early trials suggested, so expectations need to be realistic.
- At current prices, long-term cost is often a significant barrier to their use.
What Happens at a Surgical Consultation?
Meeting with a surgeon doesn’t mean you’ll have surgery. It’s simply a chance to:
- Talk through your health history and current symptoms
- Review any past test results or treatments you’ve tried
- Learn more about both surgical and non-surgical weight management options
- Ask questions in a supportive, informative environment
Your surgeon will take the time to understand your situation and help you explore what’s possible, with no pressure or assumptions.
How to Get a Referral
To see Dr Alex Craven, your GP or another specialist will need to send a referral. If you’re ready to explore what options are available for long-term weight management, it’s a great place to start the conversation.
Disclaimer: This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Everyone’s situation is different, and outcomes can vary. Always consult your doctor or healthcare provider before making decisions about your health.
Source:
Semnani-Azad et al. BMJ. DOI: https://doi.org/10.1136/bmj-2024-082007
Read the full article here: https://www.bmj.com/content/389/bmj-2024-082007
