A popular weight loss shake, Diet Fuel (produced by USN) has been on the market for years now. The formula has undergone multiple revisions – in this USN Diet Fuel Ultralean review we’re looking at whether the most current version is truly good for weight loss.
Readers please note that statements on this page are fair comment based on observation. This content is produced on a matter of public interest. Statements on this page are our honest opinion.
What Is USN Diet Fuel?
Diet Fuel Ultralean is a Meal Replacement Shake produced by USN (Ultimate Sports Nutrition).
One tub of USN Diet Fuel contains 30 servings (1kg) and costs £31.99; it is available via the official USN Diet Fuel website, as well as places like Amazon and Holland & Barrett.
The formula to this product is actually pretty simple; it’s simply a blend of whey protein, calcium caseinate and soya protein mixed with some CLA, and L-Carnitine.
The general idea of this product is that users will replace their three daily meals with a 55g serving of Diet Fuel. This means you’ll be consuming 165g of powder per day, making the 1KG tub last just about 6 days – you’ll need to use this product for at least 1-2 months in order to see any noticeable amount of weight loss.
In replacing your three daily meals with Diet Fuel Ultralean you’ll be putting yourself on a diet what is medically known as a VLCD (which stands for Very Low Calorie Diet). This is how you lose weight with Diet Fuel Ultralean, not the ingredients burning fat.. but rather the fact that you’re significantly lowering your daily calorie intake.
Does USN Diet Fuel Work?
We do not think this is a good product for long term weight loss success. VLCD’s are basically just a crash diet; essentially you’re starving the weight off your body. Once you discontinue using USN Diet Fuel you’ll probably see the weight loss quickly return.
As we mentioned above, this product does not contain any metabolism boosting, fat burning or appetite suppressing ingredients. For a product with such a high price tag we’d really expect to see at least a few powerful ingredients inside.
The main issue with VLCD is that when your body goes into starvation mode metabolic rates grind to a halt meaning that weight loss can actually be slower. When you consider that you’ll probably be feeling very low on energy and ravenously hungry all the while sticking to the Diet Fuel shake diet, it hardly seems worth it.
If you’re looking for a diet shake that will help you burn fat and spare muscle mass, this shake probably isn’t the best choice for you.
The Pros & Cons Of USN Diet Fuel
Below we’ve summarized everything we like and dislike about these shakes:
- Low calorie content.
- Contains protein.
- Multiple flavor options.
- No ingredients used inside have any solid evidence to suggest they burn fat.
- No real long-term appetite suppressing ingredients inside the formula.
- Some users have stated the taste and texture of this shake are bad.
What Are The USN Diet Fuel Ingredients?
We have found the following ingredient information on the Holland & Barrett website:
One Serving Contains: Whey protein (Milk), calcium caseinate (Milk), soy protein isolate and egg albumin powder, Maltodextrin, MCT (Medium Chain Triglycerides), Cocoa powder, CLA (Conjugated linoleic acid), L-Carnitine, Boron, Selenium, Fructose, Calcium Phosphate, Sodium Chloride, Aspartame (sweetener), Stabilizer, Vitamin Blend, and Chromium Picolinate.
Is USN Diet Fuel Suitable For Everyone?
For the most part, everyone will be able to use this product, however those with allergens to milk, soy, or egg should avoid using USN Diet Fuel. Furthermore we would not recommend it for those under the age of 18, or women who are pregnant/breastfeeding.
Is USN Diet Fuel Safe?
Based on the formula, we are confident in saying that USN Diet Fuel is completely safe; it does not contain any banned or dangerous ingredients. In addition to this, USN have an excellent reputation within the industry – we believe that they wouldn’t knowingly release a product that could cause harm.
What Are The USN Diet Fuel Side Effects?
The side effects for this product could potentially be:
- Increased bowel movements
- Stomach discomfort
- Increased thirst
- Headache 
Note: these side effects are possible but may not be the typical user experience.
Are There Any USN Diet Fuel Reviews From Customers?
We have found the following USN Diet Fuel Ultralean review testimonials:
This is quite simply a great tasting shake that’ll help you lose some weight. I swear by it (even tho it is pretty darn expensive) and wouldn’t want to diet without it!
Really was not impressed at all. It doesn’t mix well, goes all clumpy and tastes totally synthetic. I’ve given the rest of my tub away as i cannot stomach it.
Note: we cannot guarantee the authenticity of these reviews.
Our Final Verdict On USN Diet Fuel
To conclude our USN Diet Fuel Ultralean review, it’s a bit of a mixed bag – there are things that we like about it and things that we aren’t too blown away by to our readers.
It’s not a terrible product by any means, we just think that the formula is too lackluster and the price-tag is way too high for what is essentially just a protein shake with a few added extras.
There are no fat burning ingredients, so any weight loss with this product will be from a general lowering of calories – that could be a positive for some people and a negative for others.
As these shakes put you on a VLCD, you’ll probably find yourself low energy and hungry for the duration of your shake-only diet. If you are going to use this product, we’d advise you stick to a low carbohydrate diet while supplementing the shakes to replace one or two meals – ensure you’re actively exercising to get the best weight loss results.