Why you’re not losing weight on your 1200 calorie diet

The number of times I’ve heard people say they’re following a 1200 calorie diet and not losing weight, is considerable. I’ve also often heard people say they don’t eat enough and that’s why they’re not losing weight. Yet truth be told, neither of these statements are true.

And the reason they’re not true is that they can’t be. It is physiologically impossible to be in a calorie deficit and not lose weight. We know this thanks to calorimetry testing. And for most adults, 1200 calories will put them into some form of a deficit.

So then, if someone is restricting their calories and not eating much, why are they not losing weight?

Well, I’m glad you asked 😉 and here are some reasons…

  1. They’re underestimating the calorie content of their food.

A study by Lichtman et. al. (1992), assessing the estimation of caloric intake and exercise in obese subjects, found there was an overestimation of activity and underestimation of calories by up to 50%. That’s a massive inaccuracy and not the only study to show this discrepancy. However, it’s not just those that are overweight or obese who make significant errors in estimation of their food and exercise. A study by Champagne et. al. (2002) found that even dietitians underreported the energy density of their food. Now they were significantly better than the non-dietitian control group, which highlights that the more you familiarise yourself with tracking food and reading labels, the more accurate you become. Funny how that works 😉

What I have found with my clients is that when they start weighing and measuring their food, they quickly see they were eating far more in calories than they realised (with things like cheese and peanut butter being the major offenders). So even if they were not eating frequently, they were eating meals that were either larger or more calorically dense than they thought.

  • They’re not including what they’re drinking

Many people have no idea how many calories they are drinking on day-to-day basis or might not think that what they drink contributes significantly to weight gain. However, this is not the case as highlighted by Woodward-Lopez and Ritchie (2010) when they concluded that sweetened beverages accounted for at least one-fifth of the weight gained between 1977 and 2007, in the US population. And this would be similar here in Australia. As an example, something I often find is that people think they’re only having a couple of coffees each day, but those coffees are made on full cream milk and they contain sugar. Then when we actually track their coffees, a couple actually translates to 4 or 5. That can equate to a cup or more of milk (add an extra 200+ calories to your day) and 10 teaspoons of sugar, which is another 170 calories per day. They might also have something like a “healthy smoothie” which, despite being nutritionally dense, can give you a massive whack of calories for not much satiety (fullness). Before they know it, they are consuming a meal or two worth calories, in drinks alone. So, whilst you might not be eating much, what you’re drinking could absolutely be adding to your weight gain woes.

  • You’re doing less incidental activity

One of the major ways we expend energy or burn calories each day is through movement, which accounts for ~20-30% of all the calories use. When it comes to movement, it’s classified into two major groups; exercise activity thermogenesis (EAT) and non-exercise activity thermogenesis (NEAT). EAT is structured exercise or sport-like activity such as bootcamps, weights, running etc. Whereas NEAT is the incidental activity we do such as fidgeting, standing, moving around, gardening, walking the dog etc. Research has consistently shown that when we restrict our calories, our NEAT drops with it. In fact, our NEAT can become so low that is cancels out a significant portion of the calorie deficit from food.

  • Your workout quality has reduced

As explained above, NEAT is often reduced in response to caloric restriction but so too can exercise activity thermogenesis. This manifests as poorer quality workouts in addition to fewer workouts, which overall, contributes to fewer calories burned.

  • You’re eating under the critical energy availability threshold.

The critical energy availability threshold (CEAT) is the minimum energy required to keep essential physiological processes occurring i.e. a menstrual cycle and bone deposition. It’s estimated that this occurs around 30kcal per kg of lean body mass in women (it’s less clear where it is for men). To contextualise this, I weigh 65kg and have 52kg of lean mass, which means my CEAT is 1560 kcal/day. This means that for the average woman, 1200 calories is likely to be lower than their CEAT. When this threshold is exceeded, either via caloric restriction and/or excessive exercise, it causes deleterious effects in the body. This includes things like an increase in cortisol (which is oedemic and can mask weight loss progress), affecting thyroid function, causing menstrual disturbances, and affecting bone mineral density, over the long-term. In athletes, it used to be called the female athlete triad however, as it can affect males it is now called relative energy deficiency in sport syndrome (RED-S syndrome). Whilst it is more common in athletes, anyone can get it and it absolutely can impact weight loss. It also contributes to disordered eating such as the binge-restrict cycle, which can lead to eating well above our caloric requirements.

  • You’re not getting enough sleep

I’ve added this one in as an extra factor to think about. There are many things that can influence our eating habits and cause us to overconsume calories, and this blog is not meant to be exhaustive. However, approximately 33-45% of Australian adults are getting inadequate sleep so it’s worth a mention. Whilst a lack of sleep doesn’t directly affect our energy balance, what it does is it increases the chance that we will overconsume calories, affecting our ability to train properly and affects our chances of training at all. Some research has found that when we’re sleep deprived, we’re more likely to crave tasty and calorically dense foods and that we can eat as many as an extra 300 calories per day. If we are chronically sleep deprived, this could easily add up to a serious calorie surplus. Furthermore, there is some evidence that when we are chronically sleep deprived, we are less efficient at fat oxidation during aerobic exercise and we’re also less likely to train properly when we’re tired. As you can see, a good night sleep is for weight control.

So how do we fix this?

  1. First and foremost, don’t attempt an inappropriate deficit! When it comes to deficits, more is not necessarily better. You must consider what you can stick to without making you become food crazy and obsessive. Sometimes it’s better to take a gentler approach and be willing to lose weight more slowly. It’s also worthwhile getting some help with calculating your calories and macros from a qualified nutritionist or dietitian so they can help you figure out what is ideal for you, in your situation.
  2. You need to start tracking your food AND drink! The only way we will ever become more accurate at estimating our food intake, is if we do the hard work and weigh and measure everything we’re consuming. This is not something we have to do forever, but it is a skill, so it requires some practice and like any skill, the more you do it, the better you will become.
  3. If you are choosing to go into a deficit, then you need to be aware of the propensity for NEAT and EAT to both reduce. This means you need choose to hit daily step targets and fuel yourself appropriately before a workout. You can’t skip workouts because you don’t feel like doing them, and you must hit them with as much as intensity as you can.
  4. Finally, most people have no idea how important sleep is from a weight management perspective and how simple it can be to improve. You want to improve your sleep hygiene, which consists of your sleep routine, habits before bed and how sleep friendly your bedroom is etc. To improve your sleep hygiene, first establish a sleep routine. Go to bed at the same time, get up at the same time regardless of what day of the week it is. Secondly, make your bedroom sleep friendly. No TV or screens and keep your room cool and dark. You also want to consider screen time before bed as the blue light can interfere with melatonin production (our sleep hormone). And finally, try and eat a dinner that is high in fibre and protein, low in sugar and avoid drinking excessive alcohol. You also want to try and limit caffeine ~6 hours before bed.

So the next time you hear someone saying they need to eat more to lose weight or they’re following a low calorie diet and not losing weight, I hope that you can talk them through some of the issues that may in fact have them consuming more calories than they realise.

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