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Nutrition and Human Bias

Insulin making you fat?

Low Fat, High Carb? Low Carb, High Fat?

Being plant-based you could say I have a bias towards diets which promote a higher frequency of fruits and vegetable consumption.

Once upon a time, like many others, I too fell down the rabbit hole of magical diets which in theory may produce better results than others but had little to no backing or reason as to why they might work, Intermittent fasting (IF) for example.

It wasn’t until a week ago a friend reminded me that in previous years I used to preach this protocol as I once thought it was superior for fat loss based on the notion that it put you in a better ‘fat burning state’, whatever that means.

Realistically when taking into consideration our human physiology and current research on IF it doesn’t show any advantage over other diets as long as calories and equated. The anecdotal results and praise you hear from others is purely because IF allows some individuals to better adhere to a calorie deficit, and therefore, fat loss (Stockman et al. 2018; Freire 2020)

It is impossible to be completely free of bias, whether we are conscious of it or not. When I read articles and new research I try to acknowledge this fact which helps me keep an open mind towards new theories and opposing views. So when a new study or evidence comes out supporting or opposing my view I try to treat them both the same and not fall into the realms of confirmation bias (only reading or selecting studies which back your opinion or current train of thought).

Before I go ahead and talk about a recent study on energy intake (Hall et al. 2021), comparing a plant-based, low-fat diet versus an animal-based, ketogenic diet, I would like to highlight that you do not have to conform to one type of diet, and that you may wish to take into consideration other influencing factors other than your health and physique goals i.e. lifestyle, time, environment, food preference etc.

As many may preach one specific diet, you can in fact go between diets on a weekly to daily basis, the key determinant to weight loss or weight gain being calorie intake. Calories followed closely by total protein consumption, which influences where weight is lost or gained, such as lean mass (muscle etc) or adipose tissue (fat).

This new study was brought to my attention by Sigma Nutrition, if you are interested in diving a little deeper into nutritional science I would recommend giving Danny a follow.

This study primarily looked at whether low carbohydrate diets drive individuals to eat more in comparison to low fat, high carbohydrate diets when subjects eat until satisfied (ab libitum).

The aim being to dismiss the carbohydrate insulin obesity model/theory, whereby excess insulin (hormone) caused through consuming high carbohydrate foods leads to weight gain.

Each diet contained minimal processed foods, whether plant-based or animal-based.

The high glycemic plant-based diet was split into 10% fat, 75% carbohydrates and 15% protein.

The low glycemic ketogenic diet contained 76% fat, 10% carbohydrates and 14% protein.

After completing 2 weeks on either diet, subjects immediately switched to the other for another 2 weeks.

The main findings from the study found that when subjects ate until satisfied (ab libitum) the low fat plant-based diet consumed on average 690kcal less in comparison to the high fat animal-based diet.

The final week differed with only a 545kcal average between the two, both displaying a significant difference.

In this particular occasion the results nullify any grounds in which the carbohydrate insulin obesity model stood, which adds to the ever growing database of studies suggesting that hormones have little relevance in weight gain/loss and that calories are the key determinant.

Of course there will be certain case studies where this may not be the case, but for the large majority of the population calories will be king.

To put this into context, over a months period (4 weeks) this would relate to a 2,200kcal deficit, close to the daily energy consumption of an average male (2500kcal) and over the daily calorie intake of an average female (2000kcal).

If we were to look more long term this could relate to an average of 7.5 - 9.4lbs of weight loss per year.

Now these figures are extrapolated from the two week diet duration of the study, so understand that this is an estimate at best.

Being a metabolic ward study, meaning subjects were monitored in a laboratory setting over the study duration, the results will not take into consideration other lifestyle factors which may affect diet adherence or food selection, for example social gatherings or moments of weakness where it is only natural for humans to indulge.

So when can we use this data in real life scenarios?

If you are considering dieting for the purpose of fat loss, then perhaps a diet centering largely around plant-based foods, naturally higher in carbohydrates and fibre, will help adherence to the diet as it seems to aid in keeping individuals fuller and help satisfy hunger cues (bring on the salad bag).

If you are someone who finds they get hungry quite often after a meal, or has to eat a great deal before they feel satisfied, then again, a diet centered around plant-based foods will likely do a better job at satisfying you. This is partly due to a plant-based diet being higher in food volume, meaning you get more food for the calories you consume.

Take away... if you are a generally healthy individual with no record of diabetes, don’t be afraid of eating high glycemic ‘sugary’ foods and spiking your insulin level, they will not make you fat as long as your calories are in check.

Happy dieting, #dietsmart

Much love



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