A long standing theory in the diet and exercise world is the concept of a “set point”.
The physiological “set point” theory suggests that humans have a built-in regulatory system which prevents us from ever straying too far from our natural set point of weight and body fat. Like many things in life, our weight is designed to return to the mean.
Let’s break it down a little differently. I’m going to use a thermostat analogy. You set the thermostat to keep your house at 80 degrees and it continually senses the temperature via a thermometer. If the temperature goes above 80 degrees, the air conditioning comes on; if it drops below 80, the heat comes on. This is a regulated system. The set point theory suggests that humans have a physiological regulatory system in place to help control weight.
Set Point Research
A great deal of animal research is conducted on the set point model and for the most part, it tends to the hypothesis. Starve a rat and its metabolic rate slows (a slower metabolic rate demands less energy so the body needs less fuel to maintain weight). It begins to move around less thus conserving energy while its appetite goes up to the point that when you free feed it, it will eat until it reaches its starting weight at which point things go back to normal.
The same occurs when you fatten it up. Metabolic rate goes up, activity goes up, appetite/hunger go down and it eventually returns to its starting weight once you stop force feeding it.
The rat has a physiological set point.
Human Set Point Under The Microscope
Research into set point theory in humans has found similar, yet slightly different outcomes and it’s interesting stuff!
When a person diets down, metabolic rate actually decreases more than what you’d expect based on the overall loss of weight. For example, let’s say you expected metabolic rate to drop by 250 calories but when you measure it, it really drops by 375. That extra 125 calories is more than you would predict given the rat model and therefore suggests that the human body actually adapts to weight loss. This is done by not only slowing down metabolism to restrict further fat loss but it is also attempting to potentially regain body weight/body fat.
In humans, the decrease in metabolic rate is compounded by a decrease in activity and a drastic increase in appetite. We can try to compensate by tracking our activity and monitoring our food intake but the underlying instinct to decrease activity and increase food consumption will still be there. This is what makes dieting so hard! Your will power has to be strong enough to overcome feeling sluggish and lethargic while also craving food!
The most recognized study highlighting this effect is the Minnesota Starvation Experiment.
The Minnesota Starvation Experiment
This is one of the most recognized studies in this area and it’s still quoted today because it does such a good job of highlighting the effect we’re discussing.
The Minnesota Starvation Experiment was conducted during the WW2 era over a period of 6 months. A number of already quite lean male war combatants were put on 50% of their maintenance calories and made to walk a minimum of 5-6 miles per day. No exceptions - day in, day out.
Now, after reaching the lower limits of male body fat levels and showing all of the typical adaptation signs like lethargy and an obsession with food, when allowing the men to freely eat again without any restriction, they showed uncontrolled hunger and hastily ate themselves back up but this time, it was beyond their initial body weight and fat level.
The Minnesota Starvation Experiment gives us something serious to think about whenever we coach a client through a weight loss diet or fat loss phase. This uncontrollable hunger that causes over consumption is referred to as post-starvation hyperphagia. Most of us know of someone who has competed in a physique competition and rapidly packed on the pounds right after. It can literally look like on Saturday the person is absolutely shredded and by the next Saturday (one week later) you would have never known that they were just in a physique competition.
Severe dieting amplifies the adaptations seen by food restriction, whereas non-aggressive dieting sees less dieting adaptations. So essentially, the harder you want to push, the more adaptations you will see.
The quicker the result, the steeper the price. Something to bear in mind when supporting a client through a fat loss phase. Of course, what is “aggressive” to one person will be fairly easy to another. This is why fat loss coaching is such a delicate balance of programming, feedback, and adjustments.
Why Is Losing Weight Harder Than Gaining It?
Now, on the other end of the equation we have overeating. In humans, overeating doesn’t have a significant impact on increasing metabolic rate. When we look to the rat studies, it had a huge impact but we’re coaching humans here, so let’s focus on that.
Our homeostatic regulation is asymmetrical - it fights hard to protect against weight loss but doesn’t seem to be so bothered about protecting us from weight gain!
Any anthropologist will tell you why. Humans never had any evolutionary pressure to stay lean. Overabundance of food wasn’t an issue but starving to death was a very real possibility! Because of this, the body developed a number of ways of ‘defending’ against weight loss but not weight gain.
Some people will see a reasonable increase in metabolism when food consumption increases.These folks are called “ectomorphs” (or as we refer to them in our hypertrophy course, “hard gainers”). This response to overfeeding is now being called NEAT (non-exercise activity thermogenesis). Overfeeding in these individuals leads to an increase in metabolic rate as well as an increase in movement via step count, fidgeting and standing up.
These folks also seem more adept at shutting off hunger and appetite. If you know someone who claims to eat a ton and never gain weight - that’s them! Look at their food intake however and you’ll see they either aren’t eating much at all or they eat a big meal and not much else for the rest of the day.
Questions To Ask: The Set Point Debate
Human “set point” is an topic of constant controversy. Technically speaking, we have homeostatic mechanisms designed to help us maintain a stable weight but in reality, that homeostatic system is asymmetrical.
Can it really be a true set point when it favours weight gain but not weight loss?
If homeostasis controlled appetite, why do so many people have trouble with their weight?
What about hedonic regulation (reward-based appetite regulation)?
Humans Are Hedonists
Ever noticed how people will pay a lot of money to have a tasty meal prepared for them? We are a hedonic species and we love pleasure. Food is not just fuel!
Hedonic regulation (reward-based appetite regulation) can override the homeostatic system. This typically happens when energy is abundant and food is easily available. The hedonic system increases our desire to seek out and eat foods that are highly palatable.
The better something tastes, the more likely your client is to over consume it!
In recent years, sugar has become the prime suspect of weight gain. Sure, sugar tastes amazing and there has been a steady correlation between rising obesity and rising sugar consumption but from 1999 to 2013, average sugar consumption actually dropped roughly 20% while obesity rates continued to climb. What does this mean?
It means we have to think deeper than the newspaper headlines and water cooler gossip.
Sugar is not the singular cause of weight gain. The problem lies in flavour, taste, and mouthfeel - the experience of eating. When a food is fatty and salty or salty sweet or fatty sweet even fatty salty and sweet, humans are much more likely to over consume it. As a species, we value flavour so much that we’ll pay insane amounts of money just to experience it.
We live in an age of hyper palatability. Feeling blue? Try some comfort food. Celebrating something important? Treat yourself with dessert. Kids won’t eat? Order pizza. There’s a “food fix” for every scenario. This creates neurobiological and behavioral associations which can develop in to full fledged addictions.
Settling Point Vs Set Point
If a client’s environment is packed with tons of flavourful foods that are easy to get hold of and within reach with no barriers to consumption, then they are highly likely to gain weight.
It is NOT your coaching OR their will power... it’s human nature.
- On the other hand, if a client only has access to plain and bland foods, they are more likely be able to limit weight gain naturally. A person’s body weight will ultimately settle at a point relative to the environment it’s subjected to.
Perhaps it’s less about our body’s set point and more about our environmental settling point?
The question remains: what can you, as a coach, do to optimise your client’s environment so it’s easier for them?
The homeostatic system works to regulate weight by influencing appetite either up or down depending on the supply of food. The more aggressive the diet, the more excessive the adaptations.
BRASS TAX: If you regularly eat a variety of foods for an average daily total of 2800 calories and then choose to heavily reduce the volume of food, 2600 or less, you will notice an increase in appetite and a slow down in your metabolism.
Hedonic regulation can override the homeostatic system because the human body favours palatable foods
BRASS TAX: If something tastes really good, you will eat more of it. It’s much easier to eat a pound of pizza or ice cream than it is to eat plain chicken breasts or plain kale.
A person’s body weight will ultimately settle at a point relative to the environment it’s subjected too.
BRASS TAX: If you’re consistently around tasty foods, you will likely weigh more. Having a bowl of M&M’s on your desk at work is not a good idea and having cupboards filled with junk food in the event company stops by, will add more to your waistline than it does your reputation of being a distinguished host.