Weight loss diet plans are limitless – high protein, low fat, low carbohydrate, this liquid shake, that protein bar, fat thermo-burners, don’t eat at night, eat six times a day, eat one time a day – and the list goes on indefinitely. What baffles the mind is that everyone can name at least one person for whom at least one of these approaches has worked. In addition, some can think of lots of people for whom naught seems to work. The fact is, any method will lead to weight loss if, and only if, the individual attains a negative calorie balance. It is essential to keep in mind that one needs to burn more calories than one ingests for fat loss to follow.1
Undoubtedly, it is impossible to keep up with every new diet that appears on the market. So, in order to best evaluate a diet, one must not do so by the claims it makes, but rather by the foods, and therefore nutrients) that are involved and omitted. Doing so, one can best avoid the many ‘fad’ diets which, severely restrict, potentially cause damage, and demonise the process to improve body composition. Before going into the diet that I am supposed to be discussing, I just want to provide some signs that help spot these fad diets:
1. The diet omits one or more groups of foods, which implies that it may be lacking in particular nutrients or that it is too limiting for one to commit to for the long term.
2. It overstates one specific food or kind of food. The Cabbage Soup Diet is a great example of this!
3. It is very low in calories. Very-low calorie regimens can lead to greater loss of lean muscle tissue, are limited in macro- and micro- nutrients, and may diminish compliance.
4. The promoters discourage exercise or point out that it isn’t needed.
5. The diet guarantees unrealistically rapid weight loss.2
Now that I’ve got that out of the way I can finally get on with the actual diet overview. So, what is the 5/2 diet? Well, it is a form of intermittent fasting, or ‘alternate day’ fasting, which allows you to eat ‘normally’ for three days, fast for one, eat ‘normally’ for another two days, and fast for another.3 Now, what does it mean by ‘fasting’? It refers to a form of dieting called very-low-calorie diet (VLCD), containing less than 800 kcal/day (this particular diet restricts calories to 500 kcal/day for women, and 600kcal/day for men).4 It does not distinguish between individual needs, like build, height, weight, and physical activities one indulges in (personally raises a big, red flag). Moving on, the idea behind this diet allegedly originated from the Baltimore Institute of Longevity, where it was discovered that if they were to intermittently feed rats and mice, certain benefits would arise, like reduced blood pressure, cholesterol (no clarification is made on which type), better regulated blood glucose levels, increased focus and mental concentration, and Alzheimer’s-related benefits.5
How does this diet supposedly work? They claim that during a period of fasting in duration of twelve hours or more, the body undergoes a process that reduces the production of Insulin-Like Growth Factor (which is a small polypeptide, or a constituent of protein) which they state increases the fat-burning process.6 It is not stated which is reduced, as there are two known factors, IGF I and IGF II, the latter of which is not well-understood. IGF I is well-understood in relation to its effects on muscle anabolism (construction) as a result of exercise. Now, what can be eaten on a normal day? On a positive note, a large variety of food groups are included, i.e. both protein and vegetable sources. The only exclusion are baked goods (biscuits, cakes, pastries), which is to be expected in any decently-constructed diet. On a ‘fasting’ day, the basis is the same as a normal day, with the obvious exception of largely restricted portions (remember, 500 kcal for women and 600kcal for men!).7 As one can expect with a diet as extreme as this, there are contraindications, where one should not use it. Such cases would be involving children, adolescents, the elderly, and diabetics, those with heart-disease, athletes, or pregnant women. It is also recommended that you take multi-vitamin and multi-mineral tablet supplements as there will be definitely be deficiencies in these micronutrient requirements while following this diet!8
Two final notes: Firstly, as common sense would dictate, if you feel fatigued, sick, or are losing lean tissue, you must stop. Secondly, it is my duty to recommend that one visits his or her general practitioner, or registered nutritionist before embarking on any diet or eating regiment, especially one classified as a VLCD. As previously stated, any diet has the potential to aid in losing weight, but it should follow at least some of the aforementioned guidelines. Ultimately though, if it has some sort of scientific basis and is personally preferred, then go for it!
- Campbell, Bill I., and Marie A. Spano. NSCA's Guide to Sport and Exercise Nutrition. Champaign, Illinois: Human Kinetics, 2011.
- Earle, Roger W., and Thomas R. Baechle. NSCA's Essentials of Personal Training. Second Edition. Champaign, Illinois: Human Kinetics, 2012.
- Edgson, Vicki . "Vicki Edgson on the 5:2 Diet Plan." Get the Gloss | Home. Web. 4 Mar. 2013. <http://www.getthegloss.com/video/vicki-edgson-s-5-2-diet-plan>.
- Harrison, Kate. The 5:2 Diet Book: Feast for 5 Days a Week and Fast for 2 to Lose Weight, Boost Your Brain and Transform Your Health. New York: Create Space Independent Publishing Platform, 2012.
3 Harrison, Kate. "Part One: The 5:2 Revolution." The 5:2 Diet Book: Feast for 5 Days a Week and Fast for 2 to Lose Weight, Boost Your Brain and Transform Your Health. New York: Create Space Independent Publishing Platform, 2012. 15-17.
6 Harrison, Kate. "Chapter Three: The Fasting Recharge." The 5:2 Diet Book: Feast for 5 Days a Week and Fast for 2 to Lose Weight, Boost Your Brain and Transform Your Health. New York: Create Space Independent Publishing Platform, 2012. 67.