The Association of UK Dieticians describe fad diets as “the kind of plan where you eat a very restrictive diet with few foods or an unusual combination of foods for a short period of time and often lose weight very quickly.”
Examples of fad diets include: SlimmingWorld, SlimFast and the Bootea detox. However, popular diets, such as low-carb, Atkins, keto, 5:2 and caveman, are all examples of diets which can be effective and healthy for some people. So how do we know when something is a legitimate diet and not a fad that will not help us lose weight and have potentially detrimental effects on our physical and mental health?
The signs of a fad diet …
- They promise you will lose a significant amount of weight in a matter of weeks.
- They’re marketing depicts unrealistic body expectations.
- They’re marketed by influencers whose job is to promote products, not truly believe in them.
So next time, when you see an influencer promoting the sale of ‘detox teas’ and fat-burning pills, or an ad comes up online which says ‘how to lose 12lbs in 2 weeks’, remember to remain sceptical and not buy into the belief that you really can lose weight that easily.

To find out more about the real deal with dieting, I spoke to my good friend Matthew Kemp who is a qualified Personal Trainer alongside studying his Zoology with Primatology degree here at Bangor. This is what he had to say …

You can wrap as much tinsel on your new diet plan as you want…but the facts are the facts. No amount of detox tea, two week juice plans or excessive cardiovascular exercise will overpower the body’s desire to store dietary energy in adipose tissue (aka = body fat!)
To lose stored body fat, it’s a numbers game. Simply put it is calories in vs calories out – the volume of energy in the food you eat must be lower than the volume required to perform bodily functions. This is what is often referred to as a calorie deficit.
First step in working this all out is to work out your Basal Metabolic Rate (BMR). There are plenty of online calculators to do this quickly, but I would recommend the manual format to be more accurate (Harris-Benedict equation).
Once you have worked out your body’s energy demands, you’ll know what your maximum calorie intake should be. For example, if your BMR is 1,750, in order to lose weight, you must not exceed 1,750 calories of energy from your diet per day. This is the most important thing to remember if weight loss is the target. It doesn’t matter if you were to eat nothing but spinach and kale, if the calorie content in the meals you eat exceed this BMR threshold then you will gain weight. So, don’t worry too much about food types or their nutritional contents as much as your focus on the calorific content, although I would still recommend choosing healthy food options in order to fill yourself. 1,750 calories of junk food can be one meal, whereas with good food choices 1,750 calories is more than enough calories for 3 healthy meals spread out over a day.

Splits
This is where it becomes a little bit more complicated for the beginners…but don’t worry too much if this confuses you, first just focus on not exceeding your BMR threshold.
Here is how to calculate the calories in foods and how to spend your calories wisely:
NUTRIENT | VOLUME | CALORIE CONTENT |
Protein | 1g | 4 |
Carbohydrates | 1g | 4 |
Fat | 1g | 9 |
Alcohol | 1g | 7 |
I personally treat my calories like currency. So using the example of 1,750cals as the limit, we can break this down to work out how much of each macronutrient you need to cover your BMR (macronutrients = large molecules such as protein, carbs and fats / micronutrients = smaller molecules such as vitamins and minerals). A good “macro split” for starters is 40/30/30. What this means is that 40% of your calories come via protein, 30% via carbohydrates and 30% via fats. I have broken this down below to give you an idea of how this looks (bare in mind these numbers can be altered specific to each individuals needs):
BMR = 1,750 cals
Protein 40% = 700 cals
Carbohydrates 30% = 525 cals
Fats 30% = 525 cals
Protein (40%)
So if protein has 4 calories per gram you divide 700 by 4 = 175g of protein
Carbohydrates (30%)
Carbohydrates also have 4 calories per gram so divide 525 by 4 = 131g of carbs
Fats (30%)
Fats are more than double the energy value of carbohydrates and have 9 calories per gram. So you would divide 525 by 9 = 58g of fat
I personally only eat two meals a day. I skip breakfast and exercise while my body is in a fasted state to utilise my body’s stored fats. But, for the purpose of this article, let’s imagine a scenario of 3 meals a day – breakfast, lunch, dinner. Breakfast should be high in protein. The body has just been fasted overnight so will have a low amino acid content in the blood. To prevent muscle loss via catabolism a meal with good protein content will serve you well. A balanced meal for lunch and again at dinner is advised. Based on the example BMR of 1,750, I would personally advise 400 calories for breakfast, 600 for lunch and 750 for dinner – but this isn’t set in stone. This can be altered for each individual’s needs and can also vary day to day depending on the day’s demands. The ultimate message remains the same – do not exceed your BMR calorie limit!

One more additional thing to consider – alcohol. As much fun as it is to enjoy an alcoholic drink you need to take into consideration the energy content of it whilst dieting. Things like beer and wine have all kinds of additional nutrients in them used to brew and ferment the alcohol. But unfortunately the alcohol molecule itself is almost twice as rich in energy as our body’s favourite energy source (the carbs!). So a vodka and slimline tonic might sound like a get out of jail free card to enjoy boozing while dieting – sadly this isn’t accurate.
For every gram of alcohol you put in your body, you use up 7 of your precious BMR calories. And I’m afraid the bad news doesn’t stop there…when you consume alcohol your body is unable to store this like it can with the 3 main macros. As your body is unable to store this, it switches to burning alcohol as a priority. This means that the rate in which you store fat is increased and also the conversion rate of carbohydrates into stored adipose tissue is also increased. This means that not only are you consuming more calories that are hidden in your drinks, but you also slow the rate at which your body utilises the stored body fat you already possess.
If you’re truly focused on the goal to get in shape you simply have to cut the booze out – it’s a party pooper I know, but that’s the unfortunate truth relating to the biological situation regarding calories and metabolism.
Diet Plans
Now that the maths is done you can start preparing your meals. Below is a quick example of how to prepare your meal templates based on a 40/30/30 macro split:
Breakfast 400cals = 160cal/40g Protein – 120cal/30g Carbs – 120cal/13g Fat
Lunch 600cals = 240cal/60g Protein – 180cal/45g Carbs – 180cal/20g Fat
Dinner 750cals = 300cal/75g Protein – 225cal/56g Carbs – 225cal/25g Fat
In summary, you should ignore the fad diets that do the rounds. The facts are the facts and no amount of marketing or influence from personalities advertising products can ever change that. When you see professional athletes, whether this be strongmen, bodybuilders, fighters, runners, athletes, dancers or any other walk of life in the sports world….they eat real food, that is structured around their lifestyle needs and bodies energy demands.
If you are really serious about your weight management, then instead of using your time to shop for a “get rich quick” type diet, spend this time working out your BMR, calculating your macro split and then designing meal templates that fit your new diet plan.
Alternatively, get in touch with Matt Kemp Personal Training for more information and training plans!