Body weight and fat loss 101

Approx 22% body fat

Approx 15.5% body fat

Body Weight


  • Organs 

  • Bones: approx 2.5% of body weight)

  • Muscle: can't really have too much muscle, the more the better, as it improves health & longevity

  • Fat: this includes different percentages for males and females, see below for more info and includes bad fat i.e viceral fat (fat surrounding the organs) and abdominal fat (increases risk of diabetes, cardiovascular events etc)

  • Water: inside and outside cells of organs etc. This should be about 60% of total body weight).

Out of these, the only weight you should be focusing on reducing (if overweight) is fat. 

Increasing muscle is a good thing (through natural not using steroids, see 101 weightlifting for more info), as more muscles equals strength, higher calorie expenditure and health (muscle mass declines as you get older).

Side note rant (aka going off on a tangent)

FYI I disapprove of the terms weight loss and toning up. Goals should always focus on fat loss only/ increasing muscle mass. In fact I am against the use of the body mass index (BMI) for those who exercise (no matter how little) as it does not factor muscle mass/fat ratio. I believe it is only crudely beneficial for those who have a sedentary life style. I prefer the use of body fat percentage and muscle mass, which can be deduced from the use of bioelectrical impedance (BEI) scales or machines found in gyms (they use the electrical conduction to determines body composition) , callipers and DEXA scans (only available in London).

Even these methods are not accurate, they are just the same as weight scales and results may vary depending on the time, what you have drank/eaten/exercised/ peed.!. For girls they also vary at different points during the menstrual cycle. Measurements should be taken with a pinch of salt from one week after ovulation until the end of the 'time of the month' (approx 2-4 weeks after finishing the last cycle).

If anything they are good as a 'rough guide', if you are going to use them, try use them the same day/time each month.

DEXA scans are probably your best bet for accuracy, especially as they give an indication of visceral fat. You can only get this done privately in London (approx £180). They are mostly used in the NHS to investigate endocrine (hormones)/metabolic conditions e.g. osteoporosis/ bone problems in children.

There is a 'myth' that you burn less fat the older you get. This is wrong. Your body generates energy to exist. This is generated from food you consume (calories). The amount of calories you need to maintain your weight is  known as the  basal metabolic rate. This stays constant irrespective of age and does not change unless you have a medical condition (e.g hypothyroid etc) but may vary from person to person. What does change is muscle size. It starts decreasing from the age of 30 and is known as 'muscle wasting'. You don't lose huge amounts just a bit as you get older (this is related to telomere function but I'm not going to go explain this further). The more muscle you have the more 'calories' you need.  As muscle mass decreases as you become older the amount of calories 'consumed' will decrease, meaning you need to eat less. However you can combat this by weight/resistance training hurrah.! Basically weight training means you can eat more to maintain the same 'weight'. Win win.!

Body fat percentages

This is different for men and women due to the fact men have more testosterone and female have more oestrogen. Women require higher body fat percentages to allow ovulation (and menstruation) to occur. A drop below a certain body fat percentage in females results in amenorrhea (absence of menstruation). Absence for 6 months or longer (and BMI <17.5) is  called anorexia and usually indicates an eating/exercise disorder but can also be a sign of a serious health condition.

The reason why this occurs is the hormone gland in the brain (pituitary gland) shuts down to preserve energy, and therefore stops producing the hormones needed to allow periods to occur.

Whilst you may think this is a win win, it is most definitely NOT. Absence of periods increases your risk of developing osteoporosis and  endometrial cancer. Whilst your doctor can prescribe contraceptive pills to induce periods (you need at least 3 a year to reduce the risk of developing cervical cancer), I believe it defeats the point of being healthy and is a sign from your body that you need to eat more/ exercise less.

I have read females having a lower body fat percentage than 18% results in amenorrhea. However, there doesn't appear to be much scientific evidence  to back this up and it seems the percentage was plucked out of thin air  My bodyfat is between 15-16% and Im okay (sorry too much info). I believe ( FYI my opinion and not scientifically proven), that it is more related to the stress on the body. e.g. a reduction of body fat from 25% to 22% in 3 months, is more stressful on the body than a body fat reduction of 20%-17% in 1 year.

I went on a crazy cardio/ calorie restriction regime in the first year of university as I was told I was too fat (an 'elephant') and went from 59kg to 44 kg in the space of 4 months. Not surprisingly, my time of the month disappeared for a bit before reappearing after adjusting to the rapid weight loss. Not healthy at all.

This time Ive reduced my weight from 61.2 kg to 51kg, (but currently sitting around 54kg) in 15 months (whilst also increasing muscle mass). I believe, this time round there has been much less stress on my body. Hence no issues.

However, this is my personal opinion so take what I say with a pinch of salt. It is always best to seek a professional when deciding to reduce fat.

For males having very low body fat will result in reduced testosterone production. This can result in a number of issues including weaker bones, muscles, anaemia, hair loss, tiredness, low drive (you know what I mean) and infertility. Having a physique 'body' is not worth the long term damage. 

Once thing I do have to say is you should be cautious and try be mindful of your thoughts and feelings.

Food can be used as means of control/or lack of control when you have difficulties in life e.g. low mood etc. It is very easy to become obsessive/controlling/restrictive about food in an unhealthy way.

Weight, whether underweight, normal or overweight is SO complex. It isn't a simple case of calories in= calories out. It is so much more: lack of sleep, stress, depression, life style, social pressures etc.

Therefore, I must stress that you must not beat yourself up. Being overweight (not just a bit of 'cute chub) 9/10 times is usually related to mood/unhappiness or even an addiction. You wouldn't judge someone for being depressed/struggling to sleep etc. You shouldn't judge someone for how much they weigh. The problem is that because weight is so visible  people judge more. Sad but true.

What does matter and is more impressive is deciding you want to make a change. Good on you! 

Anyway I went off on a tangent. Back to the body fat percentages


  • <10 % (Very low body fat). Guys with body fat this low are usually physique athletes prepping for a competition. You would see lots of veins sticking out of their skin. This is difficult to maintain long term as it impairs testosterone production (see below for more info)

  • 10-13% (athletic aka ripped). Guys with this body fat will usually have very an '8 pack' and look 'model standard'

  • 14-18% ('toned'). Will have some ab definition 'beach bod'

  • 19-22% (average body fat): No ab definition but looks 'normal' not slim/not fat

  • 22-25% (a bit overweight): A bit 'chubby' ie some love handles but may still have some definition of arms

  • 25-30% (overweight)

  • 30+ (obese).


  • 10-12% (very low body fat). Females with body fat this low are usually physique athletes prepping for a competition. Again, you would see lots of veins sticking out. Highly unlikely that the female would have any periods at this level

  • 13-18% (low body fat). Typically have 6 pack definition

  • 18-22% (athletic). Some ab definition, 'beach body' appearance

  • 22-28% (average body fat): No ab definition but not slim or fat

  • 28-33% (a bit overweight): A bit chubby ie love handles/ under arm 'jiggle'

  • 34-40% (overweight)

  • 40%: (obese).

Nb these values are rough estimations- take with a pinch of salt people can look very different with the exact same body weight. Mostly related to bone structure/muscle mass.

If you increase your muscle mass, but don't change the amount of fat you carry, your body fat percentage will reduce by default.

Reducing fat

If there is one thing you take away from this is fat loss is 90% related to diet and 10% exercise. You can gym for hours daily but if your still eating burgers/pizza/chips daily you won't see change.


Rather than 'diet' I think the best way to lose fat is to change to a 'healthier' way of eating. 

This means cutting out anything processed or 'refined', try eat food in their natural state (inc chicken/meat/fish).

You don't need to focus on reducing calories, if you change to more natural foods you'll reduce calories by default.

Try have lots of fruit and veg. Even though 5 portions a day of fruit/veg is recommended try eat 10. When you add veg to a carbohydrate/protein meal it will help you feel fuller with fewer calories.

There is no need to hugely reduce carbohydrates unless you are completely sedentary. Even if you are sedentary you will still need some. If you are doing some exercise then you definitely need good portions of carbohydrates, helping to make you stronger, fitter and therefore work out efficiently.

You can still have cake/pizza/chips but try reduce these as much as possible.

One meal a week is fine if the rest of your week is the 'healthy food'.

If you eat out quite a lot- then try moderate the types of food you eat. E.g. half chicken and sweet potato wedges from Nandos is healthy.!

Also exclude 'empty calories', i.e mostly through drinking (inc alcohol for those who drink) and pimped up coffees (eg vanilla latte with whipped cream).

If you change to low calorie drinks you will automatically reduce the amount of calories you take and allow more calories to be consumed by food.

If you have a cravings then try control it by buying small portions of chocolate (e.g. freddo) or one pack of crisps. 

If you prepare your meals before hand and plan regular meals then you're much less likely to become 'starving' and give in to the craving of KFC/ McDonalds etc.

Remember, it takes 6 weeks to establish new habits. During the first 6 weeks you are most likely to 'relapse', have sugar cravings, eat pizza when you are not supposed to. That is okay, don't beat yourself up. This is part of being human. Just start fresh the next day. It really isn't the end of the world. Even if its a week or 2 which you struggle its fine! part of life and being human. Tomorrow is a new day :).


The best exercise for fat loss is a combination of resistance training (see 101 weightlifting) and cardiovascular exercise (e.g. running, cycling, cross trainer etc).

The resistance training helps increase/retain muscle mass. Whilst cardiovascular exercise helps 

'slow burn fat loss'.

The way I see it cardiovascular exercise makes you a smaller version of yourself whilst resistance training 'sculpts' your body to what you want.

However, studies suggest doing a combination of both is most efficient for fat loss (makes sense really as doing both will cause a calorie deficit, whilst increasing your BMR).

Try exercise at least 3 times a week. If you do 3 sessions a week then you will need to do a 'full body workout' i.e exercise to target all muscles in your body and incooperate cardio.

If you train more than 3 times a week you can split part of the body/cardio that you target.


The less you sleep the harder it is to lose fat. Simple as and scientifically proven. You're more likely to have cravings if sleep deprived

Aim for 7-9 hours and try prioritise sleep. One of the best things you can do for your health.

I think that covers the basics.! feedback appreciated. Remember don't beat yourself up if things don't go to plan. Tomorrow is a new day :)