One Day Of Overeating Isn’t Likely To Cause Fat Gain

3 min read

We all know the feelings we get from overeating.

By Phil Graham

  • The guilt
  • The bloat
  • And, of course, the meat sweats

The thought of overeating gives most fitness fanatics and dieters nightmares especially when they’re trying to lose fat.


However, most of these nightmares result from misinformation and lack of understanding of human nutrition. Overeating is overrated when it comes to fat gain. In this short article, I want to highlight 3 key points why you shouldn’t dwell on one day of overeating and in some cases, use it to your advantage.

3500kcals in 1lb of Body fat

We know that a pound of fat contains in and around 3,500 calories of energy.

Media would have you believe that you need to eat 3,500 fewer calories to lose a pound of fat or conversely, eat 3,500 calories above your maintenance level of calories to gain a pound of fat.

Is it really that simple?


Click through to find out why…

Many overeaters compensate their overeating behaviour by underrating or being more active days after

This limits the potential for fat gain as an individual’s energy balance can often be balanced out across the week to support weight maintenance and, in some cases fat loss.

I’m not a big fan of overeating one day and ‘burning it off’ the next. This yo-yo mind-set is an unsustainable way to live and will zap your energy and mood.

It takes days/weeks of overeating to store noticeable levels of excess body fat under the skin. The reality is most people think it happens after one meal. This simply isn’t the case.


There are a huge number of factors that influence body fat storage, from the time it takes food to digest, daily fluctuations in non-exercise physical activity right through to the effects of hormones.

Fat is only stored when calories are eaten in excess. To reach a level of excess requires long term over eating – not just a single meal or day.

Energy intake chases energy output. (and vice versa)

A relatively lean body senses being overfed and increases its non-exercise physical activity, to compensate for the extra energy consumed.

Talking, fidgeting and moving about more are key elements of non-exercise physical activity. In obese individuals, the message of receiving surplus energy isn’t communicated as effectively to the body due to impaired cell and hormone signalling (resistance)


The type of food you overeat matters a great deal


Calories from carbs can be stored as muscle and liver glycogen, with an average around 300 to 500 grams.

Different people have different amounts of stored carbohydrate in their bodies. Those with fuller glycogen stores are at greater risk of fat gain, while those with lower stores (as a result of exercise or planned ‘low carb’ eating) have the potential to eat more calories from carbs, before it turns to fat.

Protein’s very hard to overeat

When was the last time you overate steak?

Thought so. It’s difficult to do.

Protein suppresses appetite and boosts thermogenesis. (the body uses more energy to process it) meaning less energy is yielded than what’s stated on the nutrition label.

Carbs and fat on the other hand require less energy to process and yield more energy per gram.



Fat is stored as … fat (with little effort)

It’s easy to overeat, tastes great and packs 9kcals per gram.


Calories from alcohol are easy to overconsume (even more so when drunk).

The body burns up alcohol for energy (to avoid alcohol toxicity), which reduces the body’s ability to burn fat and other fuel sources.

Also, appetite is an issue when drinking, especially when the night comes to an end.

Take Home

The 3,500 kcal for 1lb of body fat isn’t that simple.

Not all of the food you overeat goes straight to fat storage. Your activity levels before and after eating, glycogen stores and food choice all play an important role in determining how energy from food is processed within the body.


You are what you do on average. Breaking your diet and overeating the odd time is acceptable. But frequent, unplanned periods of overeating, should force you to revaluate your end goals and strategy to get there.



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