What’s The Deal With Fad Diets? We Break Down The Top 5

When it comes to weight loss a quick fix isn’t always the right fix. Fad diets have taken the internet by storm with many people raving about their success. While some diet-goers may see short-term weight loss, research suggests that the weight loss might be challenging to maintain in the long-term (1,2).Fad diets are not sustainable for life and often cause people to regain their lost weight back and sometimes even more than their starting weight (1,2).

During the New Year it can be easy to fall into fad dieting, so here are 5 popular fad diets that you should stay clear of and how they impact weight loss, health and wellbeing.

The Ketogenic Diet

The ketogenic diet is one of the most talked about fad diets. It’s known for its ability to cause weight loss (although some research shows, not for long (5)) – but at what cost?

Keto is extremely restrictive with the diet requiring almost full elimination of dietary carbohydrates. Not only are you expected to cut out your beloved bread, but even some fruits are labelled as a no-no food! By cutting out a whole food group, it can decrease your fibre intake as whole grains are restricted. Whole grains and fibre help to make us feel fuller, and a diet high in these have been shown to help with weight loss and improve overall health (3). 

Another principle of keto is replacing carbohydrates with fat, resulting in increased fat intake. Long-term, this can promote poor heart health if the increased fat intake is saturated fat (typically coming from animal products) (4). A common symptom of the keto diet is the ‘keto flu’ which creates flu-like symptoms such as fatigue, headaches, fainting, and bowel issues – doesn’t sound fun, right! Others have claimed the diet can help with mental clarity and improve focus, however, there is limited evidence to support this.

Low Carbohydrate Diet

You might be thinking ‘isn’t keto and a low carbohydrate diet the same?’. The difference between the two is that keto completely restricts carbohydrates, whereas a low carb diet aims to reduce carb – intake but not completely remove it all together. While a low carb diet is less restrictive there is still limited evidence reported on long-term weight loss. Some evidence has supported the use of a low carbohydrate diet for medical conditions such as polycystic ovary syndrome and Type 2 Diabetes (6,7). However, it’s best to discuss the suitability of this diet for you with a health professional or dietitian first. It’s important to keep in mind that the low-carb diet may also be low in fibre. There is also a risk of missing out on the minerals and vitamins found in whole grain foods, which long-term can result in nutrient deficiencies (8).

Juice Cleanse 

You may have heard of a juice cleanse with many celebrities hopping on the trend to detox their body. However, the juice cleanse has been known to do more harm than good. Juice detoxing not only makes you ‘hangry’ but also has little benefits to your body and causes some uncomfortable bowel issues! The low energy intake of a juice cleanse will likely cause some initial weight loss due to the decrease in water weight. However once you return to your normal diet the weight tends to return (9). 

There are also claims a juice cleanse has detoxification benefits. While you may be consuming more vitamins and minerals from the juice, they cannot be used to detox your body at a faster rate, unless you previously had a deficiency. Our bodies have a natural detox process which does not need assistance by putting yourself through a juice cleanse (9,10). The current evidence suggests that a juice cleanse will also likely result in headaches, fainting, weakness, fatigue, and irritability (10). Next time you consider doing a juice cleanse, think twice and your body will thank you for it.

Gluten Free Diet

Over recent years the gluten free diet has started to be used as a tool to lose weight or improve health. However, there is no consistent evidence to suggest that a gluten-free diet can be used for weight-loss (11,12). 

It’s important to only use a gluten free diet when diagnosed with coeliac disease or gluten intolerance. A gluten free diet can result in vitamin and mineral deficiencies, and poor bone health due to the diet being traditionally lower in fibre, and gluten free flours typically containing less enriched vitamins and minerals (11,13).

 There is a common misconception that gluten free food products are healthier however this is not always the case. While gluten free products are drastically more expensive, they are more commonly higher in sugar and fat – increasing the calorie content of the food (13). If you do think a gluten-free diet is right for you it’s essential to consult with a doctor, dietitian, or registered nutritionist before starting the diet to ensure you are educated on the diet and any potential health consequences.

Paleolithic Diet 

The paleo diet came about from the theory that in the caveman era there was limited chronic disease (14). Leading people to believe that to improve our health we need to go back to the hunter-gatherer diet which is high in meat, fish, fruits, vegetables, and nuts. 

While there are some positives to the diet such as promoting the consumption of whole foods, the evidence to suggest it improves health and can result in weight loss is limited (14). This diet cuts out many different foods which might leave you feeling hungry or isolated at social events. The bottom line is that the evidence suggests that the paleo diet does not result in long-term weight loss and there is also a higher risk of nutrient deficiencies (14,15). While it’s good for our bodies to eat whole foods it’s important to not restrict ourselves and remove food groups from our diet.

Unfortunately, although they can seem like an easy fix, if you do want to lose weight a fad diet might not be the answer. It’s important to create healthy habits that are achievable and maintainable that help create long-term weight loss and wellness goals. Every food is healthy in moderation.

---

1. Hooper, B. (2014). Popular diets – what is the evidence? Nutrition Bulletin, 39(3), 284–289. https://doi.org/10.1111/nbu.12104
2. McBean, L. D., & Speckmann, E. W. (1974). Food faddism: a challenge to nutritionists and dietitians. The American Journal of Clinical Nutrition, 27(10), 1071–1078. https://doi.org/10.1093/ajcn/27.8.1071
3. Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2;393(10170):434-45. doi: 10.1016/S0140-6736(18)31809-9. Epub 2019 Jan 10. Abstract available from: https://www-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/pubmed/30638909
4. Mansoor N, Vinknes KJ, Veierod MB, Retterstol K. Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials. Br J Nutr. 2016 Feb;115(3):466-79. Abstract available from: http://www-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/pubmed/26768850
5. Sumithran P, Proietto J. Ketogenic diets for weight loss: a review of their principles, safety and efficacy. Obes Res Clin Pract. 2008 Mar;2(1):I-II. doi: 10.1016/j.orcp.2007.11.003. Abstract available from: https://www-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/pubmed/24351673
6. Tay J, Luscombe-Marsh ND, Thompson CH, Noakes M, Buckley JD, et al. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial. Am J Clin Nutr. 2015 Oct;102(4):780-90. Abstract available from: https://www-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/pubmed/26224300
7. Zhang X, Zheng Y, Guo Y, Lai Z. The Effect of Low Carbohydrate Diet on Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials. Int J Endocrinol. 2019 Nov 26;2019:4386401. doi: 10.1155/2019/4386401. eCollection 2019. Review. PubMed PMID: 31885557; PubMed Central PMCID: PMC6899277. Abstract available from: https://pubmed-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/31885557/
8. Gardner CD, Kim S, Bersamin A, Dopler-Nelson M, Otten J, et al. Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study. Am J Clin Nutr. 2010;92(2):304-12. Abstract available from: http://www-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/pubmed/20573800
9. Klein AV, Kiat H. Detox diets for toxin elimination and weight management: a critical review of the evidence. J Hum Nutr Diet. 2015 Dec;28(6):675-86. doi: 10.1111/jhn.12286. Epub 2014 Dec 18. PMID: 25522674. Abstract available from: https://pubmed-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/25522674/
10. Is a “Juice Cleanse” Right for You? (2022). Tufts University Health & Nutrition Letter, 40(4), 3. Here are some of the key features of this dynamic service to ensure that you have the latest information about food and nutrition at your fingertips (massey.ac.nz) Evidence PEN
11. Can Gluten-Free Foods Help Aid Weight Loss? – Cleveland Clinic
12. Marcason, W. (2011). Is there evidence to support the claim that a gluten-free diet should be used for weight loss? Journal of the American Dietetic Association, 111(11), 1786. https://doi.org/10.1016/j.jada.2011.09.030
13. Practice-based Evidence in Nutrition and Case S.  Are you being asked about the benefits of going gluten-free for weight loss?
14. Dietitians of Canada. The popular Paleo diet. In: Practice-based Evidence in Nutrition [PEN]. November 2014 [cited 2015 Apr 30]. Available from: http://www.pennutrition.com.ezproxy.massey.ac.nz/docviewer.aspx?id=11294. Access only by subscription. 
15. Mellberg C, Sandberg S, Ryberg M, Eriksson M, Brage S, Larsson C, et al. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial. Eur J Clin Nutr. 2014;68(3):350-7. Abstract available from: https://www-ncbi-nlm-nih-gov.ezproxy.massey.ac.nz/pubmed/24473459