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.

A Balanced Critique of the Paleo Diet

The Paleo diet, also known as the Paleolithic diet, has gained considerable popularity in recent years. 

Advocates praise its natural approach to eating, while critics question its practicality and scientific backing. This critique will explore both sides of the argument, highlighting the pros and cons of the Paleo diet.

The Case For the Paleo Diet

Focus on Whole Foods

The Paleo diet emphasises eating whole, unprocessed foods. This includes lean meats, fish, fruits, vegetables, nuts, and seeds. By avoiding processed foods, artificial additives, and sugar, followers often experience improved overall health.

Reduced Inflammation

Many proponents claim that the Paleo diet can help reduce inflammation. This is attributed to the elimination of refined carbohydrates, sugar, and processed foods, which are known to contribute to chronic inflammation.

Improved Weight Management

Due to its high protein and fibre content, the Paleo diet can promote satiety, helping individuals feel fuller for longer. This can lead to reduced calorie intake and potential weight loss.

Stabilised Blood Sugar Levels

By avoiding refined sugars and carbohydrates, the Paleo diet can help stabilise blood sugar levels. This can be particularly beneficial for those with insulin resistance or type 2 diabetes.

Nutrient-Rich Diet

The emphasis on a variety of fruits and vegetables ensures a nutrient-rich diet, providing essential vitamins and minerals that support overall health.

The Case Against the Paleo Diet

Scientific Controversy

Critics argue that there is limited scientific evidence supporting the Paleo diet's long-term health benefits. Some studies suggest potential advantages, but more comprehensive research is needed to draw definitive conclusions.

Exclusion of Food Groups

The Paleo diet excludes entire food groups, including dairy, grains, and legumes. This can lead to potential nutrient deficiencies, such as calcium and vitamin D from dairy, or fibre and certain B vitamins from grains and legumes.

Sustainability and Practicality

The diet can be challenging to maintain in modern society, where processed and convenience foods are ubiquitous. It may also be expensive, as it relies heavily on high-quality meats and organic produce.

Misconception of Historical Accuracy

The diet is based on the premise that modern humans should eat like their Paleolithic ancestors. However, anthropologists argue that the diet of ancient humans varied greatly depending on geographic location and availability of food. Thus, there is no single "Paleo" diet that can be universally applied.

Potential for High Saturated Fat Intake

Depending on the types of meats consumed, the Paleo diet can be high in saturated fats. Excessive intake of saturated fats is linked to increased risk of heart disease and other health issues.

Social and Cultural Considerations

The strict nature of the diet can make social eating difficult. Many traditional cuisines and cultural practices involve foods that are not permitted on the Paleo diet, potentially leading to social isolation or difficulty in maintaining the diet in social settings.

Conclusion

The Paleo diet offers a return to whole, unprocessed foods, which can be beneficial for many people. Its emphasis on nutrient-dense foods and the avoidance of processed items can lead to improved health outcomes, such as reduced inflammation and better weight management. However, the diet's restrictive nature, potential for nutrient deficiencies, and questions about its historical accuracy and scientific support make it a controversial choice.

As with any diet, it is important for individuals to consider their personal health needs, lifestyle, and preferences. Consulting with a healthcare professional or a registered dietitian can help tailor dietary choices to ensure they are nutritionally balanced and sustainable in the long term.