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Image courtesy of Stuart Miles /

This Debate is the first of what is going to be a new regular feature where I take a look at issues of contention/debate within the world of health, fitness and nutrition (which as no one can seem to agree on anything, should keep us going with plenty of topics for quite some time!).

In this post, I’m going to look at one of the most highly contested issues of all:

Why do we get fat in the first place, and what is the best way to lose weight?

I am going to start off by outlining the main theories surrounding this debate:

1) The Energy Balance Theory

Whether you gain weight or lose weight is simply a matter of whether you consume more or less calories than you expend. If you eat more calories than you burn, the excess will be stored as fat, and if this imbalance persists over time, eventually you will become obese.

People are fat because they eat too much, and exercise too little – The solution is to eat less, and exercise more.

2) The Fat makes you Fat theory

The theory that fat makes you fat, is really an extrapolation of the calories in vs calories out theory. What the advocates of low fat diets claim, is that because fat is much more calorie dense than carbohydrate (there are more than twice as many calories per gram in fat than carbs), it is easier for people to over eat. If someone replaces 100g of fat, with 100g of carbs, they will reduce their calorie consumption by 500kCal, which over time should lead to considerable weight loss, particularly if they also up their expenditure by taking up exercise.

3) The Carbs make you fat theory

Low carb dieters claim that it is not fat that makes you fat, but carbs. They argue that eating carbs drives insulin, which in turn drives fat storage. Over time, too much carbohydrate causes hyperinsulinaemia, which leads to insulin resistance.

They claim that when someone is hyperinsulinaemic (too much insulin), and insulin resistant (the insulin can no longer function properly), they are unable to effectively get energy into their muscle cells, or out of their fat cells. This makes them chronically hungry all the time, and means exercising will simply make them hungrier and wont have a significant effect on their fat cells.

So which, if any, is correct?

Let’s start off by looking at theory 1, calories in vs calories out. On paper, it seems to make sense, and under laboratory conditions, where energy intake and expenditure can be controlled and measured under observation, restricting calories always produces weight loss.

The problem is that we do not live in a laboratory. There are some people out there who are able to weigh and measure every meal, counting every calorie eaten, and compensating for that biscuit with an hour of drudgery on the cross trainer. I know this, because I’ve done it, and it was miserable!

These people are few and far between however, and even the most stoic will usually crack over time, as this type of dieting invariably leads to a drop in metabolism (your body will burn fewer and fewer calories meaning you have to eat less and less to maintain the same weight loss), and your appetite will increase making you hungrier and hungrier.

The energy balance proponents argue that people are naturally greedy and lazy – This is an evolutionary defence mechanism against starvation. As food could often be scarce, we are programmed to expend as little energy as possible, and when we find food, to eat as much of it as possible. The problem now is that food is so abundant we have to rely on will power to avoid over consumption.

Again, this sounds plausible on paper, but it is simply not backed up by the actual evidence.

Although we can only speculate on our ancestors’ nutritional and activity habits, there are still numerous cultures that continue to follow traditional lifestyles – From hunter gatherers, to primitive pastoralists and agriculturalists – that show this theory to be invalid. While they may not have a supermarket on every corner, their natural environments supply them with more than ample nutrition – They certainly do not spend their lives in constant misery from prolonged and sustained hunger, and yet they do not overeat and become fat.

Similarly, while they certainly don’t feel the need to expend calories needlessly by running around aimlessly or swimming to and fro across a lake for an hour every morning, all traditional cultures have their own highly energetic play, games and dance, which counters the theory that humans are naturally lazy creatures that will only move when they really have to.

It has been argued that perhaps these differences are cultural – Have we become lazy and greedy because of conditioning to consumerist and convenience culture via the media?

Perhaps there is a modicum of truth in this, but this doesn’t explain the fact that when Western foods are introduced into these cultures, they rapidly become obese and lethargic.

The Pima, a Native American tribe from Arizona have been widely studied, as within a generation of exposure to modern American foods, they had greater incidences of obesity and diabetes than did the US on average. Now of course, it must be born in mind that epidemelogical studies can never prove cause and effect, only correlation which needs further investigation. It is possible that along with SAD (standard American diet), the Pima also adopted aspects of American culture – TVs, cars, desk jobs etc, which have all also been implicated in the so called obesity epidemic.

I think, however, that the argument that the Pima became obese and diabetic because a few years of exposure to American culture made them all lazy and greedy is a little hard to swallow!

The advocates of low fat dieting, argue that the reason we are now over consuming calories, is because there is now more fat in the diet than ever before. Fat is both high in calories, and easy for the body to store as it does not require any conversion, therefore it is fat that is making us fat. If you cut the fat out of your diet, you will by default cut calories out of your diet, and therefore lose weight.

Again, this theory sounds plausible – Fat is fat, so it must make you fat, right?

Unfortunately, the evidence simply does not back this theory up. Yes, there are countries that eat less fat than the US and the UK and have much lower incidences of obesity, such as Japan and China, but there are also many other variables between our diets and lifestyles that this could also be attributed to.

On the other hand, there are plenty of cultures out there that consume considerably more fat than the US and the UK that also have much lower incidences of obesity – France, Spain and Italy in the West, and traditional cultures such as the Inuit and the Maasai.

The proponents of the fat makes you fat theory have termed these cultures “paradoxes” – A term that was almost plausible when the first one or two examples came to light, but now with so many examples of slim, healthy, high fat consuming cultures the term is laughable.

To hammer the final nail in the coffin of the low fat theory, due to the scaremongering around dietary fat that has perpetuated the health and fitness dogma over the last 40 years, dietary fat consumption in the US and UK is now at its lowest level ever, and yet obesity is higher than ever.

These so called “paradoxes” are often cited by the low carb advocates as evidence that it is not fat that makes you fat, but excessive carbohydrate.

They very correctly point out that there is no correlation between the percentage of calories consumed as fat by a culture, and the incidence of obesity within that culture. They criticise (and rightly so) those that argue against the consumption of fat for ignoring evidence that contradicts their theories, and exaggerating or manipulating studies that seem to back them up.

They also correctly point out that as carbohydrate consumption in the US and UK has increased, so have levels of obesity, and that these obese individuals are suffering from hyperinsulinaemia.

Surely then it is carbohydrate that is the problem? Or are the low carb community guilty of some of the very same crimes of which they accuse the energy balance and low fat theorists?

What about the Japanese and Chinese? By consuming a diet lower in fat than the typical Western diet, they by default consume a diet higher in carbohydrate, and yet they have significantly lower levels of obesity.

The Kitavans are an island people that still consume a very traditional diet, which at times of the year is close to 90% carbohydrate, with lots of calories coming from fruits, root vegetables and honey, and yet they are exceptionally lean and free from diabetes and other insulin related disorders. What do we have now – The Kitavan paradox?

So we have three pretty convincing arguments, all of them with notable and respected scientists putting forward compelling theories – But all of them in some way contradicted by the actual evidence.

Perhaps it would be more useful to try and identify what, if anything, all three groups can agree on?

All three groups do agree that the obese are suffering from what has been termed “metabolic syndrome”, which in part is characterised by problems with hormone signalling, in particular insulin and leptin, the two main hormones responsible for appetite regulation and fat storage.

The energy balance group believe it is over consumption of calories that causes this insulin and leptin resistance, the low fat group that it is excessive dietary fat consumption, and the low carbers that it is excessive carbohydrate consumption, but they do at least all agree that something is going wrong hormonally!

The only other uncontested nutritional fact, is that the more a culture deviates from its traditional diet, towards a more Westernised, modern diet, the fatter and more ill they become. Traditional diets can be extremely varied, from the high fat diet of the Inuit, comprised mainly of meat and fish, to the high carb diet of the Kitavans, comprised mainly of plant foods and honey.

Although at first glance these two diets may seem very different, they actually have a lot in common. Both cultures eat plants and animals. Though the first eats predominantly animals, with just a few plant foods, and the later predominantly plant foods, with a few animals, they both consume a diet of real food that is subject to little or no processing.

The other significant thing they have in common is what they don’t eat – They don’t eat processed foods, vegetable oil, refined sugar, wheat or other processed grain products.

The problem with all three of these theories of fat gain is that they are far too simplistic. The more research is conducted, the more we realise we don’t understand.

The latest theory on why we get fat is because the hormonal systems in place to regulate our appetite and metabolism are being disrupted in some way by not just one factor, but multiple agents, in modern foods.

Gluten in wheat and other lectins from grains and legumes, excessive fructose and sucrose out of its natural context, specific fatty acids from industrial seed oils (vegetable oils) and factory farmed meats, and various food additives have all been shown to have an effect on insulin and leptin sensitivity.

In addition, a deficiency in certain micro-nutrients such as Vitamin D, magnesium and long chain omega 3 fatty acids have also been shown to negatively affect hormone signalling, as has a sedentary lifestyle.

It seems that the biochemical mechanisms through which we become metabolically deranged and begin to accumulate excess fat and become ill are incredibly complex. It will more than likely take many years, and millions of pounds worth of research to even scratch the surface of what is really going on in our bodies at a cellular level.

The thing is, in the real world, none of this really matters. The answer to the question of why we get fat, and what should we do about it is simple:

We get fat, because we have stopped eating real food (plants and animals), and started eating food products that have been manufactured in a factory.

What to do about it? Stop eating food products that have been manufactured in a factory, and start eating real food again.

One of the reasons that the science is all so confusing, is because it is funded by the food industry, who are not happy with this answer. Eating real food is not profitable for the big manufacturers, therefore they will continue to dig until they find their holy grail – A cheap, high profit product that doesn’t cause fat gain, illness, depression and early death. In the mean time they will continue to bamboozle their customers with bad science and spurious claims, while continuing to sell them their toxic products.

To be more precise:

1) Cut out all wheat and wheat containing products

Bread, pastries, cakes, pasta, biscuits, and pretty much anything that comes in a box, jar, tin or packet in the supermarket.

2) Cut out all products containing industrial seed oils

Always check the label and never consume any products that contain vegetable oil, partially hydrogentated vegetable oil, sunflower oil, soybeen oil, rapeseed oil or anything similar.  Again, pretty much anything that comes in a box, jar, tin or packet in the supermarket.

3) Cut out all foods containing processed sugars

Food manufacturers use many different names to try and confuse the consumer – High fructose corn syrup, agave nectar, sucrose, galactose, cane juice crystals(!), fruit juice concentrate, and many more. In fact there are well over 50 different commonly used ingredient names that are really just disguises for sugar.  Save yourself time by simply avoiding, you’ve guessed it, pretty much anything in a jar, packet, tin or box from the supermarket!

4) Cut out all factory farmed meats and fish

Ensure all ruminants are grass fed and free range, that pork and poultry are pastured, and that fish are wild. Beware of vague terms such as grass finished, traditionally reared, outdoor bred and freedom foods.

I would recommend these as the most important dietary changes to everyone, regardless of your current health, physique or goals.

5) It could also be a good idea to cut out all grains (rice, corn, barley etc), legumes (soy, beans, lentils, etc) and dairy, particularly if you are currently overweight or suffering from a lifestyle related illness or auto-immune disease.

This will leave you with meat, eggs, fish, vegetables and fruits, and herbs and spices.

If you are overweight, and therefore likely insulin resistant, I would recommend the further restrictions of avoiding high carbohydrate fruits and vegetables. While I do not believe that these foods cause insulin resistance, they can exacerbate the problem. If you’re leg is broken, you have to stop walking on it temporarily – This does not mean that walking breaks your legs!

Stick with the strict diet for at least 28 days to give your body a chance to recover, after which time your digestion, appetite and hormonal signalling should start returning to normal.

Once you have achieved your goals – Be it reduced body fat and/or improved health you could experiment with reintroducing occasional small quantities of grains and legumes, providing they are traditionally prepared (soaked/fermented), and/or some raw, grass fed, full fat dairy.

Though it may seem difficult to stick to at first, in my experience all those that stick to the diet for the full 28 days never want to return to modern eating as they look and feel so much better from eating real food.

12 thoughts on “Diet Debate – Why do we get fat? How do we get thin again?”

  1. If the Kitvans ate a high carb, high sugar diet, but were free from ailment. Similarly the Italians, French, Japs, Chinese have a high fat, high carb/grain diet but are low obesity. Therefore why should grains necessarily be avoided completely?
    Could you not eat a home-made loaf of bread with organic flour, for instance? It would be free from all the cr@p associated with processed foods and the Italians eat home-made pasta with every meal and they’re doing ok.

    Also, what’s this stuff I read about modern forms of wheat? How modern are they and how do they differ from none modern forms? And is it possible to differentiate bewteen types f wheat used in different products?

    1. Hi Danny,

      I think you’ve sort of missed the whole point of the article there!

      Grains should be avoided, as they are one of the major causes of Western disease. The point of the article, is that this is not to do with the carbs present in the grains, but due to the lectins, phytates and anti-nutrients present in them.

      Grains, wheat in particular, have been shown to:

      Affect hormone signalling, in particular insulin and leptin sensitivity, thus disrupting fat regulation.

      Cause auto-immune disorders in genetically susceptible individuals (i.e. multiple sclerosis, arthritis, lupus etc).

      Cause bone diseases such as osteoperosis and tooth decay.

      Displace more nutritious foods from the diet such as vegetables and fruits.

      The Kitavans have a high carb diet, but it is grain free, and much lower in fructose.

      The Italians are healthier and less fat than us Brits or the Yanks, but lets face it, that’s not saying much. Its like bragging about being better looking than Robin Cook! They still suffer weight gain, heart disease, cancer, auto-immune disorders and mental illness, all diseases not present in traditional hunter-gatherer societies.

      Having organic flour would make no difference whatsoever – It would be like having organic arsenic, its still going to poison you!

      There is some research that indicates that the damage from some other grains can be minimised slightly by soaking, sprouting and fermenting them before eating, but this seems to be a lot of trouble to go for a food that will still be far inferior in terms of nutritional value to meat or vegetables.

      Don’t eat bread, eat spinach instead!

  2. Cheers mate.

    What about the ‘new’ forms of wheat/grains? This is one fo the reasons give as a cause of type 1 diabetes:

    4) The increase in type 1 diabetes corresponds to the introduction of new strains of wheat that resulted from the extensive genetics research and hybridizations carried out on this plant in the 1960s. In particular, unique protein antigens (immune-provoking sequences) were introduced with the dwarf variant attributable to alterations in the “D” genome of modern Triticum aestivum.

    Do these new grains coincide with a rise obesity and illness? Or have obesity and illness long been associated with eating bread? For example, The Romans always seemed to be eating bread, did they have the same issues we have now or is it a 20th century thing??

  3. If you actually look at the fossil evidence, humans were actually in their worst shape physically immediately after the agricultural revolution.

    Although they weren’t fat, due to having little to no sugar, little food in general and being much more active, they were much smaller in stature and had much more bone deformities due to eating a diet almost exclusively comprised of grains.

    Perhaps modern grains are worse, perhaps they aren’t – Regardless, if you’re eating plant foods, vegetables kick ass over everything else!

    1. If you are looking to lose body fat and suspect you are insulin resistant I would recommend avoiding fruits such as bananas and mangos, and starchy root vegetables, potatoes in particular.

      The best veg to go for would be green leafy ones such as spinach, kale, chard, spring greens etc, plus plenty of onions, courgettes, peppers, broccoli etc. With fruits, berries provide the highest nutrient content for the lowest amount of calories.

      Hope this helps.

  4. Hi Simon,

    This is a great article about the whole good food/bad food issue. Nicely based around fact, but with a bit of the personal touch to it.

    Many times I find that the majority of the advice you give (and that I totally agree with ) can be summed up by ‘If you can’t pick it or kill it, you probably shouldn’t eat it’.

    Sadly I can’t remember where I got it from, but it’s a good place to start.

    Keep up the good work,

  5. Pingback: What is Food? Part II: A Source of Energy | Primal Living


    we are a family living in South Africa have been reading your blog was inspired to eating correctly We believe we are over weight. have tried several diets that proved to be unsuccessful. Please send info on 28 day diet,eating plan for breakfast lunch and supper. We enjoy eating sweet potato and butternut, tinned tuna, yellow tail fish, fresh snoek curry,sago,vermicelli. Our food are home cooked prepared with:low salt low sugar spices: dried herb orfresh and traditional indian spices, ginger and garlic We drink rooibos tea black no milk no sugar no cool drinks.
    Looking forward to your reply.
    Many thanks
    Govender Ladies

    1. Hi Jennifer,

      Thanks for your comment, I am glad to hear you are finding the posts useful.

      I am not sure what 28 day plan you are referring to? The 28 days mentioned in the article was the minimum length of time I recommended making the changes suggested in the article for in order to see a difference.

      If you’d like something a little more structured, take a loog at this 8 week guide, which just requires 1 small change at a time:

      You can also find more recent and more detailed articles on nutrition on this site, for example this series of articles:

      I don’t generally recommend following a structured meal plan prescribed by someone else – everyone is different – it’s best to create your own plan based on foods you enjoy eating, preparing, and have easy access to, following the guidlines in this article/the 8 week guide I’ve just linked to.

      Overall, the foods you’ve listed all sound good choices. If you are struggling with your weight despite these healthy foods, chances are it is inbwetween meal snacks and/or cheat meals which are causing the issues. Keeping a food diary can be a very useful tool to help you be more mindful of what you are actually eating.

      Thanks again, and good luck with your goals!

      1. Hi Simon Whyatt

        Thank you for your previous email to my sister Jennifer and appreciate your advice. My sister and I have lost weight and are feeling better about our health. My sister has lost 10kgs and I lost 14kgs. I think in regards to my weight loss have plateau. I would like to ask for your advice as to how to boost my weight loss programme. I know I need to lose at least between 15 – 20kgs. My family and I are trying our best to follow your guidelines about food and health. I try to exercise between 4-5 times a week. I would appreciate any help or advice you may have.

        Be blessed always.


        1. Hi Rebecca,

          I’m glad to hear everything is going well for you.

          First thing I’d say, is do not worry. Plateaus are normal, it is rare weight continues to come off in a steady and uniform fashion, and generally, the more you’ve lost, the slower things become. Patience is always a good rule.

          My first piece of advice, would be to add in as much NEPA as possible – non exercise physical activity. Walking or cycling some or all of the way to work, the shops, or anywhere else you need to travel. If you currently get the bus or train, try walking the first few stops each way. If you have to take the car, see if you can park further from work so you walk at least part of the way.

          Secondly, find an activity you really enjoy. Could be the gym, sport, dance class, martial art. It really doesn’t matter, as long as it gets you moving, and you enjoy doing it. The more you enjoy it, the more you’re likely to stick at it and do it on a regular basis. If it’s conveniently located, and a timetable that works well with yours, and you have people to do it with (i.e. your sister, and/or new friends you meet there), all the better.

          Thanks again for your comments, good luck, Merry Christmas and a Happy New Year!

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