WonderSlim Review

WonderSlim Review (New 2020) – Can It Help You? Ingredients, Side-Effects, Results


WonderSlim Review 

The Company

WonderSlim offers a variety of dietary products, with a focus on meal replacement kits, protein shakes and protein bars. These products are presented and marketed in a way that we approve of: the focus of these products is aimed at a proper reduction of calories and increase of protein and dietary micronutrients. This is a great sign since it implies to us that WonderSlim are essentially correct in their approach to dietary interventions.

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Additionally, WonderSlim products are produced in-line with FDA manufacturing and facility regulation. These products are claimed to be “designed by experienced, licensed dietitians with specific experience in the weight loss field”, again showing that there is a scientifically-valid approach to diet and health behind these products. However, the clinical support for WonderSlim itself is minimal: whilst the site provides links and conclusions from a variety of scientific studies, these tend to focus only on weight loss in meal replacements. This substantiates some of their claims but there are problems with this. These studies were not performed using WonderSlim products, so we have no reason to prefer these products to any of the others on the market, based on the science. We’d also like to see what the literature says on the effects that meal replacements have on the preservation and development of muscle, as this is a concern health and fitness.

Protein shakes and meal replacements

3 out of 5 (mixed qualities, high costs)

As with most health and fitness companies, WonderSlim offers a variety of protein shakes with a focus on the dieting effects, satiety and low quantities of sugar, fat and calories. These shakes are generally high in vitamin content compared to other protein powder products, but have a low protein content compared to those other brands. At 15g of protein per 27g serving, this is a very low content, especially considering that these are sold as single-serving packets and in boxes of 7. This is one of the concerns that we have with the products: both in the diet kit and independently, WonderSlim products are expensive at $2 per serving (0.13c per gram of protein) vs 45c (0.0225c per gram of protein) in other, cheaper protein powders.

On balance, we’re fairly neutral on this product: whilst it offers a reasonable vitamin complex with relatively low calorie content, vitamin extracts may be low in bioavailability (WonderSlim makes no comment of the bioavailability of the vitamins in their products, and their clinical evidence does not cover this topic) and the low calorie content is only possible through a lower protein content than other market alternatives. Beyond this, the presence of corn syrup and refined fructose in the product raise some concerns about the inclusion of refined sugars, which is involved with onset of metabolic syndrome (Roberts and Liu, 2009) and diabetes (Barnard et al, 1998). Whilst this is common among protein powders – WonderSlim is definitely not the only health product to include these refined sugars – this is still something that we are concerned by. These protein shakes can have positively effects for those struggling to reach their protein requirements when combined with the fibrous fruit and veg promoted in their diet plans. However, we wouldn’t recommend the shakes alone, especially compared to market alternatives.

Protein Snacks

3 out of 5 (Mixed feelings)

Whilst the protein shakes are mostly positive, aside from a value perspective, the bars are a far more problematic product. What concerns us about them is that their sugar content is higher than the protein content in a given serving. With 10g of protein and 12g of sugar, it is hard to understand how the WonderSlim protein snack can be called a protein snack at all when it has this nutritional balance. Again, this provides some serious concerns about value: at 7 servings per $14, the protein chocolate snacks are 20c per gram of protein. When compared to other market alternatives, including WonderSlim’s own products, this is an awful value. As with the meal replacement protein shakes, the bars contain corn syrup, inverted sugar syrup and fructose. This high concentration of refined sugars is counter-intuitive to a “health and fitness” product, as the dangers have already been listed. We’d struggle to give this product more than 1.5/5.

Quite the opposite of this, the pea protein snacks are an absolute favorite. Low in net carbs (non-fibre carbs) and fats, these pea snacks contain 15g of protein and high fibre. Whilst pea protein is an incomplete protein, these make for a great healthy snack for those who also consume other protein sources. We wouldn’t rely on them to get the majority of our protein throughout the day, but they offer a delicious way to improve your macronutrient profile. We also found that they were pretty great at dealing with those salt cravings that we might get through the day – especially the more heavily spiced flavours – which means that they’re definitely fulfilling their market function as a replacement for chips and other unhealthy favorites. As with most WonderSlim products, they’re still far from cheap at $2 per bag (or 13c per gram of protein) but they present a delicious alternative to chips and can be included in the diets of omnivorous and vegan fitness-enthusiasts alike. If we were to rate them on their own, we’d give the pea protein snacks a 4/5.

Diet kits and programs

The WonderSlim diet kit is the marketing and nutritional centrepiece of the website and company as a whole. These diet kits are offered in a variety of formats in terms of the number of products provided per day and the longevity of the course. We took a look at the “core” program which provides the middling service of 5 products per day and is offered in both 2-week and 4-week kits. The cost of this product is $10.03 per day or $140.48 total – not a cheap product by any means. The value of this product is an obvious concern, especially when we consider that this is a supplement to existing dietary components. This means that, whilst some WonderSlim products totally replace meals, their core diet plans also require a variety of meals and servings that are independent of the WonderSlim product. This means that your food costs will not be $10.03 per day, but $10.03 in addition to the cost of protein, fruit or starch “servings” left up to the customer. This also seems to allow some large variables into the process.

Taking a look at the WonderSlim diet plans that they provide for both men and women, it’s clear that their claims of dietitian input are accurate. The focus on calorie balance and proper macronutrient intake demonstrates that their plans are underwritten by effective scientific theory and clinical practice: these diets are high-protein and provide guidelines promoting proper hydration and cooking methods.

There are two things that we would urge caution on with these diet plans: fat intake and calorie prescriptions. Firstly, the WonderSlim diet plan provides cookie-cutter calorie prescriptions to a wide variety of individuals who have a wide variety of body sizes and compositions. Whilst they are based on sound scientific principles, these diets have an insufficient approach to individualization: 1000-1200 calories for women is a very low-calorie prescription and does not account for the difference in total daily energy expenditure of its customers. If we are not working with the individual’s TDEE then it is very easy to over- or under-restrict calories.

Secondly, these diets promote a relatively high-carbohydrate, low-fat diet: whilst there are many benefits to eating a proper balance of unrefined, low-GI carbohydrates during a low-calorie diet (primarily related to perceptions of energy), WonderSlim products promote a fairly high proportion of these carbohydrates coming from sugars in their own products. Low fat intake makes some sense for the sake of dieting, as fats have the highest relative calorie content, but restriction of carbohydrates has shown to be clinically favourable to restriction of fats (Samaha et al, 2003; Brehm et al, 2003; Yancy et al, 2004). In addition to this, the bioavailability of various nutrients is dependent on a proper dietary intake of both fats and fibres (Brown et al, 2004; Guo et al, 2013; Roodenburg et al, 2000), as well as concerns over the Omega 6: Omega 3 ratio that is promoted by a low-fat diet. This ratio plays an important role in universal inflammatory processes (Simopoulos, 2002), meaning that low-fat, high-carbohydrate diets such as those promoted in WonderSlim diet kits might increase inflammation by prescribing high carbohydrate intake (replete with O6) and low good-fat intake (such as O3) from fatty fish and vegetables.

Concluding remarks

WonderSlim products suffer from some industry-wide problems: high refined sugar content is the result of trying to sell health to a consumer population that is overwhelmingly reliant on sugar and taste. There is a fair amount of room for improvement in their protein bars and shakes, whilst we would recommend a review of their diet kit prescriptions. However, these products are very likely to be safe and effective, even if they are poor value for money. As with most products that attempt to short-cut or replace the dietary process, it is likely to be cheaper and more-effective to book a consultation with a personal or freelance dietitian.

Related to WonderSlim: Phentaslim Review (New 2020) - Why we rate it as #1


  1. Barnard et al, 1998: ‘diet-induced insulin resistance precedes other aspects of metabolic syndrome’ in the journal of applied physiology, 84(4), pp.1311-1315
  2. Brehm et al, 2003: ‘a randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women’ in the journal of clinical endocrinology and metabolism, 88(4), pp.1617-1623
  3. Brown et al, 2004: ‘Carotenoid bioavailability is higher from salads with full-fat than with fat-reduced salad dressings as measured with electrochemical detection’ in the American journal of clinical nutrition, 80(2), pp.396-403
  4. Guo et al, 2013: ‘dietary fat increases quercetin bioavailability in overweight adults’ in Molecular nutrition and food research, 57(5), pp.896-905
  5. Roberts and Liu, 2009: ‘effects of glycemic load on metabolic health and type 2 diabetes mellitus’ in journal of diabetes science and technology, 3(4)
  6. Roodenburg et al, 2000: ‘Amount of fat in diets affects bioavailability of lutein esters but not of alpha-carotene, beta carotene and vitamin E in humans’ in American journal of clinical nutrition, 71(5), pp.1187-1193
  7. Samaha et al, 2003: ‘a low-carbohydrate as compared with a low-fat diet in severe obesity’ in The new England journal of medicine, 348, pp.2074-2081
  8. Simopoulos, 2002: ‘the importance of the ratio of Omega-6/Omega-3 essential fatty acids’ in Biomedicine and pharmacotherapy, Vol.56(8), pp. 365-379
  9. Yancy et al, 2004: ‘A Low-Carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: A randomized, controlled trial’ in Annals of internal medicine, 140(10), pp.769-777


About the Author John Wright

John has been a fitness enthusiast for over 10 years, starting out while struggling with obesity as a teenager. Over the years he has advised numerous clients on how to transform their physiques and their lives. As a writer on Nutrition Inspector he aims to help others achieve real results by staying clear of the common hype and false claims in the supplement industry! You can contact him via the "About Us" page.

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