SlimFast Analyzed

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SlimFast is probably one of the most well-known diets throughout the world, founded in 1977 in the United States, it dominates many health markets in terms of diet plans, and dietary products.

SlimFast has its own range of branded foods and a whole host of subsidiary companies that offer similar methods of weight loss.

Originally, SlimFast specialized in diet shakes for weight loss that you were supposed to use as a replacement for your breakfast and lunch. They focused on reducing carbs and calories while also suggesting to consume a low-calorie dinner with the ultimate promise of losing weight.

SlimFast now offers hundreds of different weight loss plans, products, and guides to help you reach your desired body goals. However, many people claim they’ve been on the SlimFast diet for months, even years without seeing any results, yet SlimFast themselves claim their dieting plans have been scientifically proven!

What Is SlimFast?

The SlimFast diet (sometimes referred to as the SlimFast 3.2.1. Plan) focuses on restricting your choice consuming specific meals that contain specific amounts of calories, while still allowing you to enjoy snacks, and foods you prefer to eat.

The SlimFast diet is more of a brand than it is a weight loss program, with the main focus on marketing as many of their own SlimFast products to the user as possible. Even when you’ve reached your goal, SlimFast advises you continue to consume their products in order to keep the weight off. If anything, this a very clever marketing technique to acquire lifelong customers.

How Does It Work?

The SlimFast diet works by giving you a meal structure to which you select an individual meal, or snack, from the SlimFast food list to fit into each part of your meal plan.

You pick 3 snacks, 2 meal replacements, and 1 balanced meal, hence the rebranding of SlimFast Diet to SlimFast 3.2.1.

The concept behind it is essentially that by replacing most of your food throughout the day with SlimFast products, you’ll be lowering your daily caloric intake enough that you’ll lose weight.

While this is a very simple and effective methodology, skeptics have criticized SlimFast for not appearing to be very transparent in terms of giving the consumer upfront details about the nutritional content of their products. Furthermore, critics have stated that they seem to focus on simply “reducing calories and increasing protein intake” in the hope that this “one plan fits all” type approach will work for everyone.

What Does SlimFast Allow Followers To Eat On The Diet Plan?

Throughout the entire plan, and most of the literature on their website, they recommend that roughly 80 – 90 percent of what you eat on a daily basis consists of SlimFast shakes, SlimFast snack bars, and other SlimFast products.

The only homemade meal you can eat will be restricted to 600 calories. You can also expect to see some of your snacks to consist of sticks of celery, on their own.

The Typical SlimFast Meal Plan:

  • Breakfast: SlimFast Chocolate Flavor Meal Replacement Shake
  • Snack: 1 Banana
  • Lunch: SlimFast Crunch Cereal Bar
  • Snack: Cucumber Sticks
  • Evening Meal: Spaghetti bolognese
  • Snack: 1 Apple

Will It Really Help You Lose Weight?

The Slimfast diet does focus on one of the main aspects of weight loss which is to restrict the amount of calories you consume throughout the day, however, the means by which it is achieved (replacing foods with shakes and low-calorie branded meals) is increasingly coming under scrutiny.

One of the biggest problems people face on a calorie restrictive eating program is constant hunger – the simple fact of the matter is that these types of meal plans do not typically fill you up; followers are often left wanting to eat more.

Shake-only diets are likely to leave you feeling constantly hungry and battling against the temptation to reach for a sugar filled snack, high in fat, and refined sugar.

As with any calorie-limited eating plan, you will lose weight if you follow it exactly, though followers should bare in mind that these sorts of diet plans can be extremely difficult and require vast amounts of willpower.

Those considering following SlimFast should also keep in mind that the amount of weight the average follower can lose will vary; it ultimately depends on how strict you are with following the weight loss plan. In addition to this, SlimFast isn’t what we’d consider a “diet for life” – the plan is designed to help followers hit a target goal weight – once you’ve hit that target weight you will need to migrate over to a weight maintenance program.

The biggest scrutiny that SlimFast have faced is that the program does not teach followers how to actually eat healthily, it simply tells followers to replace most of their foods with branded SlimFast products – when stopping the program, dieters will likely find it quite difficult to prevent the weight from returning.

Is SlimFast Healthy?

Again, it really depends what you chose to eat, just because the SlimFast diet makes you eat foods high in protein and low in calories, does not mean these are going to be healthy foods that contain all the vitamins, minerals and nutrients your body needs. Or indeed, the amount of nutrients your body needs.

Are There Any Risks Associated With SlimFast?

You could lose weight drastically which could lead to health problems. The best way to lose weight is over a gradual time period, not excesses amounts over a short space of time. The can have all sorts of adverse effects on your hormones, sugar levels, blood pressure, and can shock your body.

One of the main things you may experience is saggy skin, especially if you are quite overweight. Losing this much weight this fast could cause your skin to lose its elasticity.

SlimFast Is Not A Diet Suitable For Minors – The Dietary Macros Are Too Low

We do not recommend anybody under the age of 18 follow this diet plan (or any other type of VLCD for that matter), as it is simply too low in calories and nutrients for any child that may still be growing/developing.

If you feel that your child may be obese or within an unhealthy BMI range, it would be best to seek the advice and guidance of a health care professional and/or dietitian.

How To Start

Starting is very simple, simply head on over to the Slimfast official website, “pick a date” and order some meal replacements and/or snacks. Picking a date will grant you access to the “how to” guides, which will help you properly stick to the 1.2.3. program – from then on it’s simply a matter of strictly following the directions and buying in the products.


The SlimFast diet is one of the most popular, and well-known weight loss plans adopted by thousands of people worldwide. It focuses on reducing the number of calories you can eat during the day, and minimizing snacks to foods such as a piece of fruit, or a SlimFast snack bar.

It appears to be a “one size fits all” dieting plan that unfortunately has little emphasis on helping the customer understand how they actually need to lose weight, as well as very little focus on the importance of nutrition.

While following the plan can likely help you lose weight, you’ll note we use the word ‘customer’ here, as that’s exactly what SlimFast want you to be. Without sounding too harsh here, it seems to us like SlimFast want you to be a customer, not a dieter. The plan is designed to encourage you to purchase a wide range of SlimFast food products in the hope of losing weight. At least 3 of your 6 “meals” every day will be a SlimFast product.

They even tell you that in order to keep the weight off, you should be replacing at least one of your meals every single day with a SlimFast meal replacer. To us, this dieting plan seems to be encouraging you to become a lifelong customer.

A real dieting plan would teach you the importance of nutrition, and exercise, and give you the tools you need to create your own meal plans that will help to give you long-lasting results.

The SlimFast plan focuses on selling SlimFast products, not helping you lose weight. There is absolutely no telling how much weight you will lose, or if you will even lose weight. You’ll probably find that being restricted to an apple for lunch, or a hard-boiled egg for breakfast will trigger your body into craving one of their tasty chocolate shakes to satisfy your bodies calorie and sugar demands.

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Fact Checked

This article has been reviewed and fact-checked by a certified nutritionist, and only uses information from credible academic sources.