100 Years of Fad Diets: The Science, The Stories, and The Speculation

Which (if any?) diet should you choose?

For over a century, fad diets have promised miraculous weight loss and a healthier life, often in record time. 

From the bizarre to the dangerous, and occasionally to the surprisingly effective, these diets reflect our ever-changing relationship with food, body image, and wellness.

Let’s take a journey through the most notable weight-loss fads of the last 100 years, explore the “science” they claimed, and see whether any actually delivered.

🕰️ 1920s–1930s: The Era of Appetite Suppression and Food Combining

The Cigarette Diet

Claimed science: Nicotine suppresses appetite.

Reality: While technically true, smoking carries massive health risks and no reputable health authority endorses this method.

Success stories: Advertised as glamorous, but no safe or healthy legacy.

The Hay Diet

Claimed science: Mixing proteins and carbohydrates disrupts digestion.

Reality: No solid evidence supports the need for food separation. Believed it was based on old scientific knowledge that was proven incorrect. 

Legacy: Still has niche followers today, especially among alternative health circles.

The Hollywood Diet

Claimed science: Grapefruit contains fat-burning enzymes.

Reality: No enzymes in grapefruit directly burn fat. Calorie restriction is the real reason for weight loss.

Success stories: Short-term losses, long-term failures.

1940s–1950s: Crash Diet Culture

Banana and Skimmed Milk Diet

Claimed science: Low-calorie, easy to follow, nutritionally balanced.

Reality: Severely lacking in nutrients.

Success stories: Mostly short-lived due to hunger and boredom.

Cabbage Soup Diet

Claimed science: Negligible calories lead to rapid fat burn.

Reality: Mostly water loss; weight quickly returns after stopping.

Legacy: Still circulates as a “quick fix” pre-event.

1960s–1970s: Extreme Measures and High-Protein Hype

Sleeping Beauty Diet

Claimed science: Sleep through cravings = no eating.

Reality: Dangerous misuse of sedatives; highly irresponsible.

Rumours: Elvis Presley may have tried it.

The Drinking Man’s Diet

Claimed science: Alcohol doesn’t affect ketosis; carbs are the enemy.

Reality: Alcohol provides empty calories and impairs judgement.

Legacy: Proto-Atkins diet with a boozy twist.

Scarsdale Diet

Claimed science: Rigid 14-day programme combining protein and veg.

Reality: Too low in calories, unsustainable, but quick results seen.

Success stories: Short-term success, long-term regain common.

1980s: Liquid Meals and Food Combining Resurfaces

The Beverly Hills Diet

Claimed science: Eat fruit first to trigger enzymes, combine foods properly.

Reality: Pseudoscientific and highly restrictive.

Success stories: Liz Taylor reportedly tried it.

SlimFast

Claimed science: Portion control through liquid replacements.

Reality: Effective for some as part of structured calorie control.

Success stories: Long-term studies show some success when used properly.

Cambridge Diet

Claimed science: VLCD (very-low-calorie diet) triggers rapid weight loss.

Reality: Often effective but must be medically supervised.

Success stories: Many NHS-backed success stories — still used today under medical guidance.

1990s: Low-Carb Mania and Blood Type Hype

Atkins Diet (Resurgence)

Claimed science: Carbs cause fat storage; remove them to burn fat.

Reality: Ketosis works for many but can be hard to maintain.

Success stories: Millions globally lost weight; long-term safety debated.

Zone Diet

Claimed science: Balancing macronutrients prevents inflammation.

Reality: Moderate and healthy for many.

Success stories: Used by celebrities and athletes.

Blood Type Diet

Claimed science: Your blood type determines optimal food digestion.

Reality: No credible evidence supports this.

Legacy: Still popular in wellness circles.

2000s: Clean Eating and Detox Culture

Raw Food Diet

Claimed science: Cooking destroys nutrients and enzymes.

Reality: Cooking can improve nutrient bioavailability in some cases.

Success stories: Some experienced weight loss, but nutrient deficiency is a concern.

South Beach Diet

Claimed science: Avoid bad carbs and fats, focus on low-GI foods.

Reality: Sounder science, encourages balanced nutrition.

Success stories: Popular among middle-aged adults seeking moderate weight loss.

Master Cleanse

Claimed science: Detox the body with a lemon/cayenne/maple drink.

Reality: No scientific basis for “detoxing” in this manner.

Success stories: Beyoncé famously used it for a role — not sustainable.

2010s: Back to the Stone Age – and Beyond

Paleo Diet

Claimed science: Modern farming created health problems; eat like ancestors.

Reality: Removes processed foods but oversimplifies nutritional evolution.

Success stories: Many experienced improved energy and weight loss.

Keto Diet

Claimed science: Fat fuels weight loss when carbs are nearly eliminated.

Reality: Works well for some, but side effects (“keto flu”) are common.

Success stories: Widely documented success; now used for epilepsy treatment too.

Alkaline Diet

Claimed science: Alkalising foods balance body pH and prevent disease.

Reality: The body tightly regulates pH regardless of diet.

Legacy: More pseudoscience than results.

Military Diet

Claimed science: Food combinations trick the body into burning fat.

Reality: Simply a calorie-restricted plan.

Success stories: Rapid (mostly water) weight loss.

2020s: Apps, Meat-Only, and “Science-Backed” Starvation

Carnivore Diet

Claimed science: All plant foods are inflammatory; meat-only heals the body.

Reality: Highly controversial and potentially dangerous long-term.

Success stories: Some report autoimmune relief — unproven in research.

Sirtfood Diet

Claimed science: Sirtuins activate “skinny genes”.

Reality: Based on very early-stage science.

Success stories: Adele’s dramatic weight loss brought this diet fame.

Intermittent Fasting

Claimed science: Eating windows improve metabolism and insulin sensitivity.

Reality: Backed by increasing scientific evidence.

Success stories: Widespread and sustainable for many.

Noom & App-Based Dieting

Claimed science: Cognitive behavioural therapy and psychology help build better habits.

Reality: One of the more sustainable modern approaches.

Success stories: Clinical studies show moderate, lasting weight loss.

Key Notes:-

Fad diets may promise quick fixes, but long-term success still comes from sustainable lifestyle changes — balanced nutrition, movement, sleep, and stress management. Still, many of these diets sparked important conversations about food and health, even if their claims didn’t hold up to scrutiny.

Why Are Pet Food Companies Putting Rice, Seaweed, Carrots and Tomatoes in Cat Food?

If you’ve ever inspected the label on your cat’s food and raised an eyebrow at the inclusion of ingredients like seaweed, carrots, tomatoes or wild rice, you’re not alone. 

For many cat owners, it seems strange. After all, your feline friend is a carnivore, right? 

Yet these plant-based ingredients are increasingly common in modern commercial cat foods, from dry biscuits to gourmet pouches. So why are they there, and do cats even like them?

Let’s unpack this curious trend in pet nutrition.

Cats Are Obligate Carnivores: So What Gives?

First things first: cats are obligate carnivores. This means they must consume meat to thrive. Their bodies are finely tuned to digest and extract nutrients from animal tissue, not plants. 

Unlike omnivores like dogs (or us humans), cats don’t naturally seek out fruit, veg or grains. In the wild, a cat might ingest trace amounts of plant matter via the stomach contents of its prey, but that's about it.

Given that, the idea of feeding a cat wild rice or tomatoes can seem, frankly, a bit daft. And plenty of cat owners report their furry companions picking around those suspicious orange chunks in their dinner. So why do pet food manufacturers persist?

The Marketing Angle: Selling to Humans

The answer, in part, lies in who pet food is really being marketed to: you, the owner. Modern cat food packaging is often designed to appeal to human sensibilities—phrases like “with antioxidant-rich tomatoes” or “with superfood seaweed” are aimed at health-conscious shoppers, not their feline companions.

Many of us now expect our own food to include "functional" ingredients, such as kale, quinoa, chia seeds, etc., so we’re subconsciously drawn to similar features in pet foods. Brands know that a product that looks nutritious to us is more likely to end up in the shopping trolley, even if our cats would rather it didn’t.

Functional Claims: Nutrients and Additives

That said, these ingredients aren’t entirely for show. Some, like carrots and tomatoes, contain antioxidants like beta-carotene and lycopene, which are thought to support immune health. Seaweed is sometimes included as a source of iodine and minerals, and wild rice may be added as a fibre source or alternative carbohydrate. 

However, it's worth noting that the actual quantities used are usually small, and any claimed benefits are often marginal, especially when compared to the essential amino acids, taurine, and fatty acids cats get from meat.

Fillers and Fibre: A Cheap Bulk Option?

Another reason for including these ingredients is cost. Some vegetables and grains act as fillers, helping to bulk out the food without adding much expense. 

They may also be used to aid with texture or binding in dry kibble. While fibre can support digestion in small amounts, too much can reduce the overall protein content, which isn’t ideal for cats.

Do Cats Like Vegetables in Their Food?

The short answer: many don’t. Some cats will eat around the veg chunks or turn their noses up at certain flavours. Others may tolerate it, especially if the vegetables are pureed or hidden in a meat-based gravy. However, preference varies widely between individual cats.

It’s important to remember that even though cats might eat food containing these ingredients, they aren’t necessarily choosing to eat the vegetables themselves. they’re likely going for the meat-based elements and simply tolerating the rest.

Should You Avoid Cat Foods With Vegetables?

Not necessarily. A small amount of plant-based ingredients isn’t harmful, and some high-quality cat foods include them as part of a well-balanced formulation. But if you notice your cat consistently rejecting food with visible veg, or if you're concerned about the protein content, you might want to opt for a product with a simpler, more meat-heavy ingredient list.

Look for foods that list high-quality animal proteins (like chicken, turkey or tuna) as the first ingredients, and keep an eye on the overall nutritional breakdown—your cat’s protein needs should come first.

Final Thoughts

The inclusion of ingredients like seaweed, carrots, tomatoes or wild rice in cat food is more about marketing to humans and, occasionally, cost-saving than it is about feline nutrition. While these additions aren’t necessarily harmful in small amounts, they’re not vital to your cat’s diet either.

In the end, your cat’s instincts still know best: if they sniff, nibble, and walk away from a “wild rice and tomato delight”, they might just be telling you they’d prefer something a little less trendy—and a little more meaty.