When it comes to having success with training and nutrition, psychology trumps physiology. Here are five reasons why that's true, along with what you need to know to avoid the mistakes that hinder your gains.

1 – Eating High Reward (Supernormal Stimuli) Foods

High reward foods are very calorie dense and often very tasty. They're generally high in added fats and/or sugar, and the reward properties of these foods may also be enhanced through the use of salt or monosodium glutamate (MSG).

High reward foods are "supernormal stimuli," sometimes called a supernormal releaser. The term, which is from ethology (the study of animal behavior), refers to a behavioral phenomenon whereby animals respond more intensely to stimuli that are exaggerated versions of the normal stimuli with which they evolved (1,2,3).

Here's a fun example. The Australian jewel beetle has a body that's big, long, and brown. The males are hard-wired to like certain features of the female, namely largeness, brownness, and shininess. So what's really large, brown, and shiny? A beer bottle. That's right, the males attempt to copulate with a type of discarded brown beer bottles called "stubbies."


Just as animals respond more strongly, and often preferentially, to the exaggerated (supernormal) stimuli, humans can respond similarly to exaggerated versions of foods.

This isn't to suggest you might mate with a pork chop. It just means these high-reward foods can act as supernormal stimuli and can lead to maladaptive eating behaviors that hinder fat loss and promote fat gain. Here are two of them:

  1. Consistent and continued consumption of high-reward foods (the supernormal stimulus) can render whole foods (a normal stimulus) less appealing or unappealing.
  2. The influence of supernormal stimuli has changed what people think is a "large" portion size for a single meal. Research in 2006 replicated a study that was done in 1984 in which participants were asked to serve themselves an amount they considered to be a typical portion of each item on a buffet table (4).

The 2006 study found that peoples' perceptions of what they consider to be normal portion sizes have changed in the past 20 years. As you might guess, they've grown larger. Much larger. The researchers called this "portion distortion" (5). Exaggerated portion sizes can serve as a supernormal stimulus that distorts your perception of appropriate amounts to eat at a single meal.

Keeping the above two points in mind, not only can high-reward foods cause you to be less satisfied by whole foods (and therefore make adherence to a diet that emphasizes whole foods more difficult), but also more likely to eat larger portion-size meals.

Given this phenomenon, it makes sense to minimize exposure to high-reward foods, or at least be continually aware of portion sizes.


2 – Paying NOT to Go to the Gym

A 2006 research paper found that across 24 subgroups (gender/club/age), gym members expected to go to the gym an average of ten times per month, but the average monthly attendance was lower than 4.75 visits for 23 out of 24 groups, with an overall average of 4.17 monthly visits (6).

In effect, about 80% of members overpaid by around $700 per year. They would've been better off with a per-visit plan, but the most important finding of this study isn't about dumb financial decisions, but about the role human psychology and behavior plays when it comes to going to the gym.

It all comes down to overconfidence. According to the authors of the paper, "Overestimation of future self control or of future efficiency is at the root of all findings." These findings also apply to consumer behavior in the credit card industry and employee choice of 401(k) plans (6).

In layman's terms, we call it wishful thinking. Here's what to do about it:

  • Look at how often you've actually gone to the gym each week over the last few months and create a realistic goal based on that. In other words, make small changes based on your previous behaviors – not big changes based on what you think you should do.
  • You may want to regularly work out 3 to 4 times per week, but if you're someone who's previously averaged one workout a week or less, it's smarter to start out by making it a goal to train at least twice per week. Then, every month or so, you can do just a bit more than you did before. That's what gradual behavior change – changes that are much more likely to become habits – is all about!
  • It's smartest to start off by buying a temporary membership to a gym to see how often you'll actually go before committing to a long-term contract. Or, if you're looking for group training classes, first buy something like a multiple-class pass or do a pay-per-visit setup for a short while before you commit long term.

And, if you're looking for individual guidance from a personal trainer (like myself), I recommend first purchasing a few sessions before you buy a big package of sessions.

Once you realize you've found a comfortable environment that you can return to consistently, you'll be far more likely to succeed.

3 – Using an Approach that Doesn't Fit Your Personality Type

In 1985, Deci and Ryan described three personality types (7):

  1. Autonomy Oriented
  2. Control Oriented
  3. Impersonal Oriented

Autonomy Oriented

These individuals don't like anything rigid that takes away from their ability to be self-determining. They much prefer making their own decisions on what they do.

For example, they dislike a repetitive and rigid workout structure. They're more motivated when they're able to make (at least some) decisions on things like exercise order, certain exercises they prefer to perform or omit that day, or changing the style of the workout depending on how they feel.

The same applies to their nutrition. They don't want to be put on a specific diet plan but prefer to be given guidelines that allow them to make decisions.

Control Oriented

These folks have difficulty staying on track unless they're training for a specific event. People with this personality type do best with very structured programs and diets with clearly defined metrics and markers.

Control-oriented people are the opposite of autonomy-oriented people. They really like training for specific events, transformation challenges, or any approach that offers incentives (a trophy, special T-shirt, gift card, etc.) to keep them interested and motivated.

Impersonal Oriented

These individuals tend to say things like, "I've tried everything but nothing works." Once things do get going in the right direction, they tend to suffer setbacks. They might get hurt or have a major life crisis.

Because of this, they're often hesitant to start training at a new facility or embark on a new exercise or nutrition program. That's why they tend to do best with training and nutrition direction that starts off slowly to build comfort – one that takes place in a supportive environment with constant communication and social support.

Ultimately what's important is realizing which personality best describes you and then making the appropriate decisions about your training and nutrition.

Group Fitness

4 – Social Loafing

Social loafing describes the tendency for people to expend less effort when working in a group than when working alone or in a small group (approximately 2-4 people). A meta-analysis of 78 studies showed that social loafing is common across many tasks and populations (8).

These people may come to a group exercise class with the intent of working hard, but their social loafing tendency causes them to slack off. Sure, some group class-instructors are better than others at managing social loafing, but even the best instructors can only do so much when they're in charge of a large group.

This is why social loafers would do better with semi-private training where this type of loafing is far less likely to come into play while still being a bit more social and affordable than one-on-one training.

5 – Falling for the Availability Bias

The availability bias, sometimes called the "availability heuristic" (a mental shortcut), explains the tendency that leads us to rely on immediate examples when evaluating a specific topic, concept, method, or decision (9).

This plays out by putting too much importance on examples of things that readily come to mind in our decision-making process.

Great examples of this in the exercise realm include when a celebrity gets in great shape for a movie role or when a high-profile athlete wins a big fight. Suddenly, everyone wants to know what type of workout program they used, and you can't swing a dead celebrity trainer without hitting an article or video about this "amazing" transformation.

Subsequently, because of all this media coverage, people think it's the best workout around and they want to copy it. What they should be thinking is, "Man, there's a lot of media overkill on this person's workout. It must be because they're desperate to stay relevant and keep up with their media competitors."

Don't pick your exercise direction based on what's popular, but rather on what's important. Workout trends come and go fast, but what matters in exercise success is consistency and effort.

Furthermore, you should base your exercise direction on your ability and preferences, which are determined by your personality type, your medical history, and ultimate goals. That's a winning formula for long-term success that will never steer you wrong and never be outdated.

Related:  7 Mind Hacks for Gym Dominance

Related:  The 6 Stages of Transformation


  1. Alcock, J. Animal Behavior: An Evolutionary Approach. Sinaur Press: Oxford, MA; 1975.
  2. Staddon, J. A note on the evolutionary significance of "supernormal" stimuli. American Naturalist 109(969): 541-545, 1975.
  3. Tinbergen, N. Social releasers and the experimental method required for their study. Wilson Bulletin 60: 6-51, 1948.
  4. Guthrie, H. Selection and quantification of typical food portions by young adults. Journal of the American Dietetic Association 84(12): 1440-1444, 1984.
  5. Schwartz, J, and Byrd-Bredbenner, C. Portion distortion: Typical portion sizes selected by young adults. Journal of the American Dietetic Association 106(9): 1412-1418, 2006.
  6. Stefano DellaVigna & Ulrike Malmendier. Paying Not to Go to the Gym. American Economic Review, American Economic Association, vol. 96(3), pages 694-719, June, 2006.
  7. Deci, Edward & Ryan, Richard. (1985). The General Causality Orientations Scale: Self-Determination in Personality. Journal of Research in Personality. 19. 109-134.
  8. Karau, Steven J.; Williams, Kipling D. (1993). "Social loafing: A meta-analytic review and theoretical integration". Journal of Personality and Social Psychology. 65 (4): 681–706
  9. Gilovich, T. D.; Griffin, D.; Kahneman, D. (2002). "Heuristics and Biases: The Psychology of Intuitive Judgment". New York, NY: Cambridge University Press.