The Issues With “Eat Less, Move More” – Why Common Weight Loss Advice is Not as Helpful as You Would Hope
Dr Sean Wheatley, MSc, PhD. Science and Research Lead
When trying to lose weight, people are often encouraged to “eat less, move more”. As if it is that simple! In many cases, little to no further guidance or support is provided – just those four words, and then you are on your own.
Where additional information is given, it invariably involves a focus on low calorie (usually low fat) foods, with the emphasis being on what they do not contain rather than what they do.
This blog looks a little further into the wisdom of such advice, and why “eat less, move more” should ultimately be the outcome, not the method.
What makes us eat?
In relation to weight management, managing hunger is key. What we eat has a bigger impact on body weight than our activity levels. So although there are also flaws with the “move more” part of common weight loss guidance, the “eat less” side of the equation is the most important here.
When the body has access to sufficient energy (from what we have eaten and/or what we have stored in the body) and has been provided with enough of the nutrients it requires to function, hunger should be turned off. We should not therefore feel the desire to seek more food.
Of course, things aren’t quite this straightforward in practice, as people often eat for other reasons, including:
– psychological reasons (e.g., due to stress, habit or boredom),
– social reasons (e.g., when going out with friends food is often involved; or due to people bringing food into work, for someone’s birthday for example),
– due to environmental pressures (e.g., food – and usually junk food – is available almost everywhere, making it difficult to avoid and often leading to temptation).
It is beyond the scope of this blog to cover these. But for long-term weight loss to be achieved any non-biological drivers of eating need to be identified and addressed too. We will put these factors to one side for now though, and return to biological hunger.
Biological Hunger
So, different foods influence hunger in different ways. This then influences eating behaviour, which, in turn, affects hunger (and so on). If we don’t choose foods that reduce hunger a meaningful amount and/or for a meaningful amount of time this can become a vicious cycle. Food choices should therefore be guided, at least in part, by how they will affect hunger. But instead, the “eat less” part of the guidance that has become central to weight loss efforts for many focuses solely on trying to manipulate energy balance (i.e., by trying to reduce “calories in”) with no consideration for the impact of what is eaten on hunger levels.
As you will see (and probably already can), this can cause problems.
Eat Less, Move More – Limitations
Before we get further into limitations linked to human biology, there are other practical issues with the “eat less, move more” message.
The first is that this guidance is dripping with accusation. It implies that people are in complete conscious control of these things. The natural extension of this is that it is therefore the fault of the individual if they have gained weight, or if they are unable to lose it. It suggests that people are overweight because they are greedy and/or lazy. This perspective is completely wrong. But it is unfortunately widespread. The stigma attached to this does nothing but make weight management even harder.
The second issue is that this advice is entirely unhelpful. Telling someone with obesity to “eat less and move more” is like telling someone who is in debt to “spend less and save more”. If they were able to do so consistently, it would of course solve the problem. In reality though, it provides absolutely no useful information on how to achieve what is being suggested. It does not consider why people are overeating (and/or not moving enough, though, as mentioned above, dietary factors are more significant in the obesity picture in most cases).
Following advice to “eat less, move more” is often possible (and even effective) in the short-term. But without considering the underlying issues it is usually only a matter of time before things start to turn. Willpower can only usually get us so far.
Once we are past these practical concerns, there are a number of biological flaws with the “eat less, move more” method.
Biological Flaws
One of these issues has already been alluded to. Our body needs nutrients. When people eat less, and focus solely on calories, they often end up cutting out many nutritious foods. This is because lots of healthy, nutrient-dense foods (which often contain healthy fats and/or high-quality proteins) are not inherently low calorie. As a result, the body ends up being deprived of key nutrients. So it triggers hunger to try and make us go and get them. These nutritious foods tend to have other positive effects when it comes to reducing hunger. Such as by taking longer to digest and thus helping us to feel fuller for long. The choices that traditional “eat less” advice often lead to are therefore unhelpful when it comes to managing hunger in multiple ways.
Another key biological limitation of this messaging is down to compensation that occurs within the body. If attempts are made to manipulate “energy in” (by eating less) and/or “energy out” (by moving more) without considering the underlying drivers of these things the body is likely to adapt to try and keep things how they were.
Compensation Example
For example, the body triggers hunger because it thinks it needs energy and/or nutrients. If you eat less (without considering what you eat), the body will think it is being deprived. This means it is liable to go into what is often referred to as “starvation mode”. Note: this is also linked to the way different foods affect the hormones – such as insulin – that control fat storage and energy usage in the body, but it is beyond the scope of this blog to cover this. The consequence of this is reduced energy expenditure. With the body reducing metabolic rate (the energy it is burning) to try and preserve the fuel it does have available to it.
Other Considerations
Other compensatory actions can include reduced spontaneous physical activity (through reducing energy levels) and/or increased hunger.
All of these actions make it more difficult to lose weight (and/or to maintain weight loss). They can be reduced or removed by ensuring what you do eat is providing the body with what it needs.
Prioritising quantity (i.e., the amount you eat) at the cost of quality (i.e., the types of food you eat) is therefore unhelpful when it comes to managing hunger. By extension, it is unhelpful when trying to manage body weight. These biological limitations means that the “eat less, move more” method often puts us in combat with our own body. A battle we are unlikely to win.
What’s the alternative?
So rather than only thinking about how much we eat, a shift of mindset to prioritise quality may be more productive. Note: “quality” foods does NOT have to mean expensive foods; real foods like vegetables, pulses, eggs, tinned fish and certain cuts of meat will provide plenty of nutrients without having to cost too much. When it comes to hunger, the key is to focus on what is being eaten. If better choices are made, this should naturally result in less being eaten, because hunger is reduced. It should also lead to increased activity levels, because people feel more energetic.
Importantly, energy intake being reduced as a result of eating better quality foods and so being more satiated is not the same as consciously restricting calories. Also, physical activity being increased (largely subconsciously) as a result of feeling more energetic is not the same as deliberately increasing exercise with the primary aim being to increase energy expenditure.
The main difference is that consciously trying to manipulate energy in and/or energy out will likely be met by resistance and compensation from the body (as noted above) if we don’t address the reasons for why we are hungry and/or lethargic in the first place.
Therefore, “Eat less, move more” should be the outcome, not the method. That is to say, we should end up naturally eating less and moving more. As a result of making healthier food choices (leading to reduced hunger and increased energy levels), rather than specifically setting out to try and consciously control this.
So, what should I eat?
The role of different foods in determining hunger, weight management, and general health could (and does) fill whole volumes of books. It is therefore clearly not possible to cover it fully here. In general though, choosing minimally processed foods (and avoiding ultra-processed ones) will go a long way towards helping most people to achieve their health goals.
Foods that are high in protein are generally particularly good at promoting satiety. As such we recommend basing your meals around a good source of protein. High fibre foods tend to be good at reducing hunger too.
For further information, why not take a look at our “What I Need To Know” leaflet series. This series includes information on a range of different dietary approaches, as well as guidance on how to tell the difference between real and ultra-processed foods and further information about protein (including its benefits and good sources of it).
What’s the bottom line?
People are often told to “eat less” and “move more”, but this advice rarely leads to long-term weight loss. This is in part because it provides no useful information on how to do this in the real world. In part because the body will often compensate for changes you make. And in part because it doesn’t take into account that different foods have different effects in the body (including on hunger).
You can flip the story though, by focusing on eating better, rather than just trying to cut calories. Making healthier food choices will help to reduce hunger. This will lead to you naturally eating less, and increase energy levels, leading to you naturally moving more. This will help with weight management and with general health promotion. “Eat less, move more” should therefore be the outcome, not the method!
