Eating Habits: Snacking and Hunger

Hunger and satiety genes:

FTO gene and constantly being hungry:
The FTO gene was identified in 2007 in a genome-wide association study (GWAS) that looked at over 35,000 people to determine which genes were involved in obesity.[ref] More recently, researchers have discovered that FTO acts as an RNA demethylase. This means that the protein encoded by the FTO gene acts to regulate the gene expression of other genes.

LEPR gene and hunger:
encodes the leptin receptor. Leptin is the hormone that signals your long-term body fat to the brain as a signal of whether you should eat more.

GNB3 gene and being Hangry (angry when hungry):
A study looked at a group of 108 patients undergoing a modified medical fasting treatment for 8 days. The participants had a total energy intake of fewer than 350 calories/day. When looking at the daily recordings of both hunger and mood, researchers found that a genetic variant in the GNB3 gene was associated with greater hunger and worse mood when fasting. This same GNB3 variant also links to an associated increased risk of being obese. Often, you will see it referred to as a metabolically ‘thrifty genotype. The fasting diet did work for weight loss regardless of the genotype, but those with the genetic variant had ‘pronounced mental discomfort’.[ref]

💡 Hunger and Satiety Ideas:

1. Try eating a small protein snack just before a meal. Or eat the protein portion of your meal first.  Research shows that eating protein first, followed by carbs and vegetables, causes a smaller peak in blood glucose levels. This should result in less hunger after a meal.[ref]
2. With the GNB3 variant, look into ‘time-restricted eating’ instead of longer fasts or intermittent fasting. Time-restricted eating is based on the idea of eating during the same time window each day, such as between 8 a.m. and 6 p.m, and then not eating at night. This puts your eating pattern in sync with your circadian rhythm which gives some of the benefits of fasting without the Hanger.
3. Try eating more slowly, letting your ‘full’ signal catch up. For example, cut your sandwich or hamburger in half. Eat half of it, and then take a little break before eating the second half.

Sweet Tooth Genes:

FGF21 and sugar intake:
The FGF21 gene codes for a hormone created in the liver and is important for appetite regulation. In addition to stimulating adipocytes (fat cells) to take up glucose, FGF21 also is involved in signaling in the hypothalamus to suppress sugar intake and alcohol consumption. The hypothalamus is a region of the brain that is important for appetite control and overall metabolic rate

💡 Sweet Tooth Ideas:

1. FGF21 is also involved in ketone production on the ketogenic diet. There doesn’t seem to be solid evidence in humans, though, that a ketogenic diet won’t work for someone with this variant. However, if you find that you don’t do well on a keto diet, you may want to go with a balanced diet of whole, unprocessed foods.
2. FGF21 is also important in the control of body temperature. Cold exposure upregulates FGF21 and increases brown fat activation. Look into exposing yourself to cold, such as turning the shower on cold for a bit.[ref] A note of caution: While cold exposure is often generally considered beneficial for healthy people, I would suggest caution if you are dealing with a chronic condition since it can be stressful to the body.

Snacking Genes:

Snacking between meals can pack in a lot of calories, so for many people, stopping the habit of snacking can help with weight maintenance.

LEPR gene:
The leptin receptor is important in getting the “full” signal and not wanting to eat more.

💡 Snacking Ideas:

1. Leptin resistance is believed to be caused by leptin levels being high, but yet the brain isn’t getting the signal from the leptin receptor to stop desiring food. Leptin resistance is also thought to have an inflammatory component, with higher inflammatory cytokines adding to impaired signaling.[ref]
2. Look into ‘leptin resistance’ diets for a leptin reset. Leptin resistance diets are usually based on whole foods and avoid processed carbohydrates.

Emotional eating or eating disinhibition:

Some people overeat when stressed or worried. Others tend to overeat whenever presented with an excess of tasty food, such as at a holiday meal or all-you-can-eat buffet.

TAS2R38 (bitter taste gene):
The taste receptor for bitter controls how you perceive certain flavors. People who are unable to taste bitter may have different eating habits.

GAD2 gene and emotional eating:
This gene encodes a part of the GABA neurotransmitter, which acts as an off-switch for certain neurons. Changes in the receptor are linked to emotional eating and wanting to eat more.

💡 Eating Disinhibition Ideas:

1. Keto? A ketogenic diet enhances GABAnergic inhibition in the brain when used long-term. It is one way through which it helps with epilepsy.[ref]
2. Bone Broth: Glycine receptors are also inhibitory chloride channels – and there is cross-talk between glycine and GABA-A receptors.[ref] Glycine is abundant in bone broth and gelatin.