Experts break down seven popular diets and reveal which is best for your health goals

Here’s what you should try — from the Mediterranean diet to intermittent fasting — depending on your goals, as well as what to avoid.

We’ve all heard someone, at some point announce, “I’m trying keto” — usually in the months leading up to a big event. Or perhaps you recently caught up with a friend, only to find out they’ve started the Mediterranean diet because they’ve heard it will help them to live longer.

Diet trends have come into and gone out of style for decades (think back to the ‘Wine and Eggs’ diet of the 1970s). Each brings with it a round of bold claims about how it can improve energy, complexion, gut health and so on.

In recent years, however, we’ve become more aware of the benefits of tailoring our diet to our own body, including eating for endometriosis, menopause, perimenopause or even just eating to complement your menstrual cycle.

But beyond health conditions, many popular diets touted on social media don’t work the same for everyone. Metabolism, genetics, blood sugar and lifestyle all play a role in how our bodies respond to food. Add specific health goals — like better sleep or muscle building — and you’re often left guessing.

Is there one single healthiest diet?

According to Daniel Herman, founder of Bio-Synergy, the answer is a resounding no. Every diet or eating approach has its own logic, benefits, pitfalls and audience that it serves.

As Daniel puts it: “Some diets are genuinely good for heart health or metabolic resilience, while others are best treated as short-term tools, not lifelong systems. And some are simply placebos wrapped in clever branding.”

According to Daniel, the healthiest diets include plants, fibre, whole foods, healthy fats, lean proteins, diversity and minimal ultra-processed fillers. “But the exact ratios matter far less than people think,” he adds.

Ultimately, the most effectible diet is one that you can follow easily and stick to long enough to let your body adapt to it. Personalised nutrition based on medical testing and lifestyle assessment is ideal.

For those still keen to trial a novel way of eating for the new year, here’s our expert-guide to diets, including which ones serve specific goals — and which fall short.

Read more: You won’t believe this diet published by Vogue

The Mediterranean diet

Best for: heart health, longevity, gut health, energy stability, inflammation control and long-term metabolic health

Centring around whole plant foods, healthy fats and lean proteins, the Mediterranean diet owes its enduring popularity to the idea that it’s “nutritionally well-balanced, minimally restrictive and highly sustainable”, says Emily Somers, registered associate nutritionist (ANutr) and behaviour change coach at Voy.

Benefits:

• Promotes cardiovascular health, blood sugar balance and longevity.
• High in fibre for gut health.
• Antioxidants from fruits, vegetables and olive oil reduce inflammation.

Pitfalls:

• High-quality ingredients like olive oil, fish and nuts can be expensive.
• Cultural adaptation may be needed for some, as it’s rooted in Southern European cuisine.

Low fodmap

Best for: IBS, chronic gut issues

Low fodmap diets follow the pattern: elimination, reintroduction, personalisation — usually beginning very restrictively with only meat, poultry and certain vegetables (and then reintroducing other food groups one by one from there).

Designed for medically diagnosed IBS, this short-term elimination diet helps identify trigger foods. “Great when used with purpose; problematic when used without one,” says Daniel.

Benefits:

• One of the most effective methods for reducing IBS symptoms such as bloating and abdominal discomfort
• Helps pinpoint trigger foods
• Provides clearer long-term digestive comfort when completed properly

Pitfalls:

• Not meant for long-term use; prolonged restriction can reduce gut-microbiome diversity
• Complex to follow, professional guidance recommended
• Poorly executed attempts can lead to unnecessary long-term restriction

Read more: Gemma Collins reveals the new diet that helped her drop two dress sizes, and it’s actually sustainable

Keto

Best for: short-term weight loss, blood sugar control

This high-fat, low-carb diet aims to shift the body’s metabolism to burn fat for energy. It typically involves lots of meat, poultry, dairy, non-starchy vegetables, nuts, seeds, berries and healthy fats such as avocadoes.

It sounds healthy at first glance, but since it avoids all types of carbohydrates, it’s not widely recommended by experts for long-term use.

Benefits:

• May improve blood sugar control (under medical supervision)
• Used therapeutically for neurological conditions like epilepsy
• Can help manage metabolic conditions

Pitfalls:

• Its restrictive nature makes it challenging to maintain long term
• Can easily result in nutrition gaps if not carefully planned and may demonise carbohydrate intake despite them being the brain’s main energy source
• High reliance on animal-based foods reduces sustainability

Read more: Does going vegan or vegetarian mean risking nutritional deficiencies?

Vegan diet

Best for: long term sustainability, digestive issues, environmental awareness, longevity, heart health, reduced inflammation, gut microbiome diversity

A plant-based diet that avoids all animal products (such as dairy and meat), Emily Somers notes that it’s one of the most sustainable diets, but “plant diversity is key” for microbiome health.

For Daniel, supplementation is non-negotiable when it comes to the vegan diet, as it’s important to meet your standard nutrient needs, especially for vitamin B12.

Benefits:

• High in fibre, antioxidants, and phytonutrients, supporting heart health and reducing inflammation.
• Can help with weight maintenance.
• Can improve cardiovascular health.

Pitfalls:

• Vegan diets require thoughtful planning to meet needs for vitamin B12, iron, zinc, omega-3s and iodine, so could result in nutrient deficiencies
• Heavy reliance on ultra-processed meat substitutes may limit nutritional value and those with higher protein requirements may need to be more intentional with meal balance

Vegetarian diet

Best for: healthy weight management, maintenance, metabolic balance, overall longevity, gut support

Adding back in eggs and dairy products makes this diet much more flexible than veganism, however, processed substitutes is where many stumble.

Benefits:

• Less restrictive and often easier to follow long term
• Eggs and dairy provide additional protein and micronutrients
• Typically higher in fibre, supporting heart and metabolic health

Pitfalls:

• Risk of low iron, zinc or vitamin B12 if variety is limited
• Can become overly carbohydrate-heavy
• Protein intake may require more attention

Read more: Feeling sluggish this winter? Your protein intake could be the reason

Gluten-free

Best for: coeliacs, those with genuine gluten intolerances

Emily notes that while, of course, a gluten-free diet is necessary for those with diagnosed intolerances, it “can require more effort to include whole grains, such as quinoa, buckwheat and oats if certified GF, which can be harder to prepare”.

Daniel adds that, despite the hype, gluten-free diets are only medically essential for a small percentage of the population. “For everyone else, removing gluten often does more harm than good — especially when swapping traditional bread for heavily refined gluten-free replacements.”

Benefits:

• For coeliac or diagnosed sensitivity, it can dramatically improve digestion and nutrient absorption and quality of life
• Can be diverse and balanced when built on naturally gluten-free whole foods

Pitfalls:

• Gluten-free processed foods are often low in fibre and micronutrients
• Any perceived benefits in non-sensitive people usually stem from reducing ultra-processed foods, not gluten removal itself

Intermittent Fasting

Best for: weight management, metabolic improvements, short term weight loss

Intermittent fasting involves eating within a set window each day and fasting outside of this period.

“Intermittent fasting is appealing because it strips nutrition back to timing,” says Daniel. “For some, limiting eating to specific windows — whether a 16:8 pattern or an easier 12:12 — naturally reduces calories and improves metabolic markers with almost no conscious effort.”

Benefits:

• May support insulin sensitivity in some individuals (although those with medical conditions should seek guidance)
• Structured eating windows can reduce grazing on high sugar, high-fat products throughout the day and improve appetite awareness
• Can support weight management without strict food rules

Pitfalls:

• Not suitable for those who are pregnant, underweight or have a history of disordered eating
• Early stages can cause fatigue, irritability or overeating during eating windows
• Some people thrive on structure, while others find prolonged hunger psychologically stressful or risk slipping into disordered patterns

Read more: You’re probably not eating enough fibre — here’s why you need more

Carnivore diet

Best for: people with specific medical guidance, usually those with severe autoimmune conditions

A peculiar diet to have been making the rounds in the past few years, the carnivore diet is super-restrictive, fibre-free and deeply polarising, according to Daniel.

Followers eat only animal products, such as meat, eggs and some dairy, while eliminating all plant-based food.

He stresses that, at most, it should be used as an experimental elimination tool at the very start of a medically supervised protocol or as a “very short-term intervention for those specifically advised to try it”.

Benefits:

• Some people report short-term digestive relief due to removing fibre and fodmaps
• The high protein content can support satiety and initial weight changes
• There are anecdotal reports of symptom improvements, although these haven’t been validated in long-term research

Pitfalls:

• Excludes all plant foods, leading to major gaps in fibre, antioxidants and essential micronutrients
• May negatively impact the gut microbiome and can raise LDL cholesterol
• Lacks evidence on long-term safety
• For the general population, it poses significant long-term risks due to nutrient deficiencies

Always be sure to seek medical advice before beginning any new diet.

Feature image: Unsplash