One of the things that seems especially unfair in life is that some people have to pay a lot of attention to every bite they consume to stay at their ideal bodyweight. Meanwhile, others seem to be able to gorge on anything they like and still stay slim. How can this be possible?
There is no single answer to that question since there are behavioural, nutritional, and genetic factors at play. However, a key factor is entirely unrelated to metabolism or body type – it’s perception.
While some people may seem to be able to eat anything and not gain weight, in fact they aren’t eating any more food than you are. For example, someone who eats chocolate every day may be naturally compensating for the additional calories that they’re consuming by eating a small meal for dinner or by having fewer snacks during the day.
Many people become frustrated when they see some people seemingly eating anything they like without ever putting on any weight. However, perception has a vital part to play in this. Very often, these people who seemingly gorge on high fat snacks all day long aren’t actually consuming a surplus of calories.
To put on weight, we must be in a calorific surplus, which means that we have to be taking in more calories than are being burnt during the course of the day. If you consume a low enough number of calories you can only eat chocolate and still stay slim. Of course, eating sugary and fatty foods make it much more difficult to keep a low calorie consumption, but it’s still a key point to keep in mind.
So, how can someone who appears to be constantly stuffing their face with fast food not be in a calorific surplus?
The first possibility is that the individual may not actually be eating a lot. If you think that somebody who consumes fast food every day for lunch should be bigger than they really are, it’s important to be aware that they may overall consume a fairly low level of calories. They may be eating a burger and chips for lunch, but they may just have fruit for breakfast and a salad for dinner. Although their diet may not be especially healthy, that doesn’t mean they’re over-consuming.
Another possibility is that the individual has a well-rounded diet overall, but all you see them eat is junk. A coworker who always appears to be eating cake and biscuits at the office may appear to be eating an unhealthy diet, but it’s very possible that when they’re at home they eat well. Somebody who appears to eat food that is fattening and unhealthy may not have an entire diet made up of those unhealthy foods. It’s very possible that their other meals contain plenty of healthy and nutritious foods such as fruits, vegetables, and lean proteins.
Another possibility centres around the number of calories that the individual burns. Somebody may simply need to consume more calories during the day because their metabolism is higher. Some people have a metabolism that is naturally higher than that of others. It’s important to note that things such as muscle mass, hormones, and age all have a part to play in the number of calories we need to consume every day, so in some cases, an individual’s calorie intake needs can be far higher than somebody else’s.
Finally, it’s possible that the individual may just be extremely active. While they may sit at a desk in the office all day at work, they may go for a run in the early mornings then hit the gym straight after work. They may also have higher levels of NEAT exercise due to fidgeting, pacing, or walking around more during their day.
Essentially, the factor that counts is caloric balance – anybody can, at least in theory, consume anything they like without gaining any weight as long as their total calorie intake is balanced with the total amount of calories that they expend during the day.
Does Physical Activity Matter?
While physical activity level make a difference, that doesn’t necessarily mean that the person you’re thinking of who appears to be able to eat doughnuts all day is spending hours in the gym. It’s a fact that some people move more, even when they aren’t athletes.
For example, their job may be very active, or they may chase their children around all day. They may even spend more time pacing or fidgeting. There’s also evidence that shows some people have a genetic predisposition to move their bodies, revving up their metabolism and the amount of energy spent by their body during the day, even without doing any formal exercise.
Little evidence exists to suggest some people can genetically burn a lot more calories than other people even without doing any exercise, although there could potentially be some physiological differences which allow some individuals to moderate their calorie intake naturally without having to use a lot of self-restraint. Hormones and signals from our nervous system tells the body when it’s full or when it’s time to eat, and in some individuals, that appetite regulatory system is more sensitive than in others.
Do Genetics Matter?
Research has shown that genetics do have a part to play in whether we tend to lose or gain weight. People who are naturally slim often have fewer genes linked to obesity. However, genes aren’t the only factor involved in determining weight, and they cannot exclusively protect an individual from becoming or obese or, conversely, predispose somebody to be obese. This means that, while our likelihood of maintaining or gaining weight isn’t actually predetermined, it’s also something that we cannot entirely control ourselves.
While there isn’t a genetic switch allowing some individuals to eat anything they like and not gain any weight, it also doesn’t mean that an individual gains weight solely because they lack any self-control.