How Knowledge of Hunger and Appetite Regulation Can Guide Practical Advice

Introduction

I have now discussed all of the primary components of hunger and appetite control, both centrally in the brain and peripherally in the rest of the body. With this information there are several insights regarding choices you can make to influence your hunger and appetite levels, which can aid the dieting process if you are attempting to lose weight and may be of interest in other scenarios as well. I will summarize some of the more relevant points of the prior articles while providing these practical insights.

Practical summary points with tips

Here I will list various summary points, with associated background from the prior articles and then relevant tips.

It takes time to experience satiation after beginning to eat.

• Background: As demonstrated previously, signaling of the arcuate nucleus of the hypothalamus (in both the AgRP and POMC neurons) changes in anticipation of eating presumably to prepare for the postprandial state, but satiety is not experienced until the various GI peptides and relevant signaling occurs. Thus, it is very easy to eat more than necessary simply to abate hunger if you tend to eat very quickly.
• Tips:
  1. You can counteract this by purposefully eating slowly.
  2. Alternatively, you can eat a relatively small serving of food and then wait 15-20 minutes prior to consuming a second portion if you so choose.

Various acute sensory information strongly impacts appetite and hunger.

• Background: The sensory information can override natural physiologic hunger signals. Examples of this include when portion sizes are larger than needed or when small individual portions of many distinct foods are available. Many people will eat all of the food they are presented, even if this full quantity of food is not needed to achieve satiation.^{(Hetherington, 2019)}
• Tips:
  1. You can counteract this by only preparing or ordering appropriate portion sizes and decreasing the diversity of foods available. Be mindful of portion sizes at restaurants and order accordingly. When you are preparing food, utilize some mechanism to ensure the portion sizes are appropriate. If you are eating a snack (ie, potato chips), take out an appropriate serving of the snack and eat this rather than eat the snack from the source as the latter will likely lead you to eat more than is needed.
  2. Another strategy when you do not have direct control over the portion sizes is to adopt a health-focused mindset.^{(Veit, 2020)} Think to yourself how much of this food you should eat for health purposes, and realize that after you have tried the food for several bites there is no reason to expect any novel sensation from continuing to eat it. By thinking about eating for health as opposed to eating for pleasure it will be easier to cut yourself off at an appropriate point; you can always take the remainder of the food home to eat at a later time.

Hedonic signals are strengthened when in a state of hunger.

• Background: When you are hungry you are more likely to “give in” and have treats that are available, or at the very least you will need to exert more “willpower” to avoid them.
• Tips:
  1. One way you can get around this is to try to prevent yourself from ever getting to the point of being very hungry. For some people this is achievable by having regular meals and snacks; perhaps while dieting you may have a persistent low level of hunger throughout the day but if you can avoid significant spikes in hunger this can help you avoid binging episodes.
  2. Alternatively, some people will find that if they engage in intermittent fasting (in the research world this is referred to as “time-restricted eating” or “time-restricted feeding”) then this will help curb their hunger during their fasting window, potentially due to ghrelin production being entrained to circadian rhythms, ketone production with prolonged fasting (particularly when dieting at a caloric deficit), or some other mechanism. You can read more about the research regarding meal timing here. Whether this will work for you will likely come down to personal preference and you can consider engaging in this strategy if you would like.

Different macronutrients have variable impacts on satiation and satiety.

• Background: Generally, regarding satiation and satiety, protein > carbohydrate > fat, and consuming foods with soluble viscous gel-forming fiber will also contribute favorably.
• Tips:
  1. You can use this to your advantage by increasing your protein and fiber consumption when dieting to lose weight.
  2. At the same time, you can decrease consumption of foods rich in simple carbohydrates and/or tasty fats.

Foods high in both carbohydrates and fats seem to trigger hedonic signaling more than other foods.

• Background: Foods high in carbohydrates and fats activate the various pleasurable taste sensation pathways in addition to generally being conceptualized as more appetizing.^{(Edwin Thanarajah, 2023)} This increases the expected reward from eating them.
• Tips:
  1. You can try to remove all of the tempting highly palatable foods from your local food environment (both at home and at work). If you keep the oreos, chips, and other highly palatable snacks out of your home, then even when you are hungry you most likely will not develop cravings that are so strong where you feel the need to go run out to a store to purchase those foods. This doesn’t mean you can never have these treats, and in fact it may be a good idea to have them occasionally to help prevent any specific cravings from becoming too strong. The key would be to purchase and consume the treats outside of the home in relatively small quantities rather than to buy large amounts of the treats and bring them home with you.
  2. You can still consume many healthy food options high in carbohydates (ie, whole-grain bread) as well as fats (ie, peanut butter), even together (ie, peanut butter sandwiches) without significantly increasing your hedonic drive to eat. It is the more highly-processed, sugar-filled, unhealthy fat-laden products (ie, cake) that will predominantly trigger hedonic signaling.

Decreasing caloric intake to lose weight will increase hunger levels.

• Background: As soon as you begin in a caloric deficit and lose weight your leptin levels will start to decrease, signaling to the body that energy stores are low and leading to increased hunger. This may only be partially abated by shifting your macronutrient intake as indicated above.
•  Tips:
  1. One potential way around this is to incorporate more physical activity as well as intense exercise sessions. Moderate-to-vigorous intensity exercise can acutely induce satiety and strengthen satiety signals.^{(Blundell, 2015b; Taylor, 2018)} Thus, not only will this directly help abate hunger, but this will also lead to greater caloric expenditure, meaning you can eat slightly more calories and still lose weight effectively. The increase in caloric expenditure may only work to a point, as discussed here, but you can consider adjusting the intensity and timing of your exercise sessions to see if this will help you manage your overall hunger.
  2. Another strategy it to take short “diet breaks”, perhaps for 2-3 days at a time, every so often where you increase your calorie consumption to maintenance levels. By increasing predominantly carbohydrates to achieve this there may be a rise in your leptin levels, temporarily offsetting some of the metabolic alterations that occur with continued weight loss, and helping to (temporarily) decrease your hunger levels.

There is an important distinction between “hunger” and “appetite”.

• Background: Appetite ratings will not necessarily correlate with energy intake as hedonic influences are only partially influenced by homeostatic energy regulation considerations.^{(Holt, 2017)}
• Tips:
  1. When feeling drawn towards eating certain food, you can ask yourself “Do I want this or do I need this?” or “Am I actually hungry right now or am I just craving this?” If you do not feel that you need it and are not legitimately hungry, then your hedonic system is currently active and pushing you towards a certain food. If this is the case:
     1. either have a small portion of the food to satisfy that craving
     2. remove yourself from that location so you cannot access the food
     3. consume something else in place of that food (ie, if you are craving something sweet and candy is available, have a few grapes instead)
  2. Find something else to do or focus on to distract you from any provoking food items. While this is not an ideal way to cope with actual hunger, if you can determine you are primarily being influenced by appetite at any given time point then shifting your focus to a different task may help abate any hedonic signals.

Homeostatic and hedonic influences intermingle in your subconscious.

• Background: The hypothalamus is a key regulator of homeostatic energy balance considerations, and it receives input from peripheral signals and the hedonic system. However, the homeostatic signals are mixed with hedonic influences as they transcend to the conscious decision-making parts of your brain. Thus, it can be difficult to know if the hunger you are experiencing is solely due to a physiologic need for energy or if it is being amplified by your emotional state, stress, or some other ongoing experience.
• Tips:
  1. You can consider keeping a diary that tracts hunger. Just note down when you are experiencing higher than typical levels of hunger and anything associated with this (ie, poor sleep the night before, feelings of anxiety, etc). Then you can track this over time to determine what other aspects of your life may be contributing to elevated hunger levels and attempt to directly work on these to help minimize their influences.
  2. You can simultaneously track appetite, the strength of cravings, etc, and use this to help determine underlying factors that are making the dieting process or healthy eating in general more difficult.

The hedonic system can experience habituation.

• Background: As you begin to “give in” to cravings the relevant signaling pathways can strengthen over time. This will make you prone to continuing the same habits.
• Tips:
  1. It is important to realize that changing these habits will be most difficult at the beginning. As you continue to break them over time (ie, by avoiding certain food items, or limiting yourself to smaller portions, etc) the strength of the habituation and associated feelings/emotions should decrease. Realizing this aspect of dieting will get easier over time can make the initial harder stages (of this component of dieting) seem more bearable.
  2. If you can find other things to do in place of the prior habits (ie, have a small serving of yogurt with fruit as dessert instead of a large piece of cake and ice cream) this can further help diminish the hedonic influences and help your brain and body adopt to your new, presumably healthier, lifestyle.

Obesogenic diets can disrupt the homeostatic hunger-regulating mechanisms.

• Background: Obesogenic diets generally refer to dietary patterns consisting of highly processed foods with simple carbs and tasty fats and relatively little fruits/vegetables/lean protein sources/etc. Activity of AgRP neurons in the hypothalamus seems to be disrupted by following an obesogenic diet, and hedonic influences on these neurons seem to shift body weight and/or adiposity settling points upward.
• Tips:
  1. To counteract this, avoiding a classically obesogenic diet is ideal. Thus, try to avoid ultra-processed foods, foods high in sugar or tasty fats (and especially both), and sugar-sweetened beverages.
  2. Consuming obesogenic foods once in awhile will not make a big difference, but if you are in a location or situation that lends itself to obesogenic eating habits regularly (ie, your workplace frequently orders fast food), you can try to make healthier choices from the available options (ie, choose a grilled chicken sandwich without any special dressing as opposed to a double cheeseburger with lots of sauce).

Obesity alters hedonic signaling.

• Background: People with obesity can have increased activation of hedonic brain areas upon presentation of highly palatable food cues.^{(Brondel, 2022)} Obesity causes a decrease in dopamine and opioid receptor expression in hedonic signaling areas as well as a decrease in taste sensation^{(Archer, 2019)}, but does not necessarily decrease underlying hedonic drive, necessitating greater amounts of food consumption to generate the same total amount of hedonic pleasure.
• Tips:
  1. This can make it even more beneficial for people with obesity to avoid situations where they will be prone to consuming highly palatable foods as they may naturally want to consume greater amounts to achieve the same desirable effect.
  2. With weight loss some of these changes should reverse; this should allow people with obesity to eat smaller amounts of these foods while still feeling satisfied, which is helpful.^{(Oustric, 2018)} However, if a person does not realize this, they may continue to eat larger amounts than necessary out of habit. Thus, it can be important to intentionally eat smaller quantities to allow your body to adjust favorably.

The most influential sense for hedonic signaling may be smell.

• Background: Various sensory information is processed in the brainstem and/or the thalamus, with one exception: smell. Smell is directly processed in cortical regions, and for this reason the sense of smell may exert stronger hedonic influences than other sensory information.
• Tips:
  1. It may be particularly important to avoid food odors, relative to food images or other food cues, that would trigger the desire to eat highly palatable foods.
  2. You can track over time how different types of food cues impact your hunger and appetite levels and then adjust your lifestyle accordingly.

Poor sleep and higher stress can contribute to increased hunger and appetite.

• Background: The stress hormone cortisol has many different roles in the body, and this can increase hunger and appetite (in part by stimulating increased ghrelin and NPY as well as decreasing the brain’s sensitivity to leptin and insulin).^{(Kuckuck, 2022)} Poor sleep has several negative health implications and can make individuals more prone to eating in excess.^{(Liu, 2022; Papatriantafyllou, 2022)}
• Tips:
  1. Taking steps to optimize your sleep is worthwhile. This may include adjusting the room temperature (generally slightly cooler is better), blocking out ambient light, using something to block or drown out various noises, having a consistent bedtime, putting away screens ~1 hour before bedtime, avoiding naps, and attempting to relax in some way prior to sleeping. There will be a lot individual variation with this; if you feel refreshed upon waking and do not get overly tired throughout the day then you are likely sleeping well.
  2. Combating stress can be difficult; obviously removing the source of stress or dealing with it head on is helpful if feasible. Otherwise finding hobbies to focus on to help take your mind off stressful situations, leaving work at work, undergoing therapy, or finding some other ideally healthy form of stress relief can be quite beneficial.

Obesity and weight loss decrease postprandial secretion of the GI satiety signals.

• Backgound: The satiety peptides likely do not play much of a role in increasing hunger but they do have some influence in helping to induce satiation when eating. With both obesity and weight loss these hormones are secreted in smaller amounts. This may be part of the body’s mechanism to maintain the higher body weight and will make weight loss efforts more difficult.
• Tips:
  1. This makes it more important to be mindful of portion sizes or calories counts. If people with obesity simply eat to the point of feeling full, they may naturally eat more than is necessary.
  2. While dieting many people will experience some level of hunger most of the time; you can try various dietary tips and strategies to alleviate this but it is hard to completely account for all of the changing physiology and fully eliminate hunger. If you can accept this fact and change your expectations to tolerate a relatively small increase in your general hunger levels the weight loss process will likely be easier. You can look forward to being able to increase your calorie intake when your weight loss journey is complete (while still maintaining your new lower body weight) as described in the example here.