Ultra-Processed Foods
Ultra-processed foods target the brain’s reward system, not satiety: the constant food noise is not weak willpower but an engineered dopamine effect.
Ultra-processed foods do not target satiety; they target the brain’s reward system. By activating the dopaminergic[G] nucleus accumbens[G], they create “food noise”—constant craving that reflects not energy need, but overstimulation of the reward system. Their high energy density[G], minimal protein and fiber content, and rapid consumability bypass natural satiety signals. Reducing UPF[G] intake is one of the most powerful tools for stabilizing appetite signals.
Ultra-processed foods do not target satiety, but the brain’s reward system: by activating the dopaminergic[G] nucleus accumbens[G], they create “food noise”—constant food cravings that reflect not energy need, but overstimulation of the reward system. UPFs have high energy density[G] (see Chapter 13), minimal protein and fiber content, and rapid consumability that together bypass natural satiety signals. Reducing UPF[G] intake is one of the most powerful dietary interventions for stabilizing appetite signals.
Why Do UPFs Cause Overeating?
Ultra-processed foods are designed to bypass natural satiety mechanisms. The so-called hyper-palatability (excessive palatability) is based on carefully proportioned sugar-fat-salt combinations—these combinations activate the dopaminergic[G] system of the nucleus accumbens[G], characterized by mechanisms similar (though less intense) to those that maintain addictive behavior patterns.
“Food noise” is the consequence of this sustained dopaminergic[G] activation: the UPF[G]-consuming patient does not eat continuously because of hunger, but because the brain’s reward system receives constant stimulation. This is not a weakness of will, but a biological response to a designed effect.
Eating speed is also an important factor. UPFs are easy to chew and rapidly consumable, meaning that the hormonal feedback conveying fullness has no time to reach its target. GLP-1[G] and CCK[G] secretion reaches the brain 10–15 minutes after eating begins; leptin[G] levels begin to rise 15–20 minutes after eating starts. If eating finishes in 5 minutes, these signals “lag,” and the brain delivers the fullness signal late—by then we have already eaten too much.
The Effect of UPFs on the Microbiota
Ultra-processed diet has a direct effect on the microbiota. High UPF[G] intake reduces the diversity of gut bacteria and particularly worsens the ratio of Bifidobacterium[G] and Lactobacillus[G] genera. The mechanisms include: a low-fiber diet reduces the amount of fermentable substrate; emulsifiers (polysorbate-80, carboxymethyl cellulose) have been shown in animal studies to directly disrupt the mucus-bacterial boundary (Chassaing et al., 2015, Nature) [159]; their human relevance is still being investigated; some additives may have antimicrobial properties that reduce diversity.
Deteriorating microbiota[G] composition feeds back on appetite regulation: reduced SCFA[G] production weakens GLP-1[G]/PYY[G] satiety signals, increasing LPS[G] translocation increases systemic inflammation and impairs insulin sensitivity[G]. Reducing UPF[G] and increasing fermentable fiber intake therefore act synergistically on microbiota[G] and appetite regulation.
How to Reduce UPF Intake?
The most important principle of UPF[G] reduction is gradualness. It is neither necessary nor realistically possible to abandon all processed foods overnight. The effective strategy: identification, then step-by-step substitution.
The first step in identification is monitoring liquid calories: soft drinks, fruit juices, and sugary coffee drinks are the easiest-to-reduce and metabolically most harmful parts of UPF[G] intake, because liquids do not activate mechanical satiety mechanisms and raise blood sugar very quickly. Eliminating these alone can bring significant change.
Introducing slow eating—at least 15 minutes per main meal—allows GLP-1[G] and leptin[G] signals to arrive on time. This does not mean prolonging eating, but conscious chewing, pauses between bites, and putting down utensils while eating.
What Counts as Ultra-Processed Food?
The concept of ultra-processed foods is defined by the NOVA[G] classification system (Monteiro et al., 2010). The question is not whether food is processed, but to what degree it has undergone industrial processing and what ingredients it contains. The most characteristic ingredients of UPF[G] are: flavor enhancers (glutamate, inosinate), emulsifiers (polysorbate-80, carboxymethyl cellulose), artificial sweeteners, modified starches, texture agents, dyes, and preservatives—these ingredients are added through industrial processing, not home kitchen preparation.
Among the four NOVA[G] groups, typical examples of group 4 (ultra-processed) — the classic 100+ ingredient category (Monteiro et al., 2019):
- carbonated soft drinks, energy drinks, sugary sports drinks
- packaged sweet and savory snacks (chips, granola bars, crackers)
- mass-produced bakery items (packaged white bread, brioche, long-shelf-life pastries)
- breakfast cereals with glazes, flavorings, and added sugar
- instant soups, instant noodles (with flavor sachet)
- hot dogs, sausages, deli meats, reformed meat products
- chicken nuggets, breaded frozen meat products
- ice cream, packaged desserts, flavored dairy products
- packaged yogurt and cocoa drinks (sweetener + flavor + thickener)
- “healthy” or plant-based UPFs (vegan sausage, meat-substitute burgers, protein bars)
- formula-based meal replacements (Soylent, Huel, MyProtein meal replacement)
- sweetened, flavored “plant milks” (rice, oat, almond drinks with sugar, oil, stabilizers)
Three-day goal summary: to understand that ultra-processed foods cause overeating and unstable appetite through their effect on the reward system, energy density[G], and eating speed; and to establish a food pattern that reduces UPF[G] intake and stabilizes hunger signals.
- UPF[G] sources identified in the Lifestyle Log
- At least 2 daily meals from whole food ingredients
- Avoidance of sugary drinks and liquid calories
- Daily fluid intake target minimum 1.9 liters (morning 2x200ml, daytime minimum 1.1l, evening 2x200ml)
- At least 7500 steps/day
- Hunger scale shows more stable values
Why do ultra-processed foods cause overeating?
- Neurobiological effect: UPFs[G] do not target nutrient need, but the brain’s reward system. Hyper-palatable sugar-fat-salt combinations trigger nucleus accumbens[G] dopamine[G] response, overriding natural satiety signals.
- High energy density[G]: Exceptional calories per gram, minimal fiber and protein—satiate briefly (see definition of energy density, Chapter 13).
- “Food noise”: The energy crash following rapid blood sugar elevation creates biological compulsion (craving) to eat again. This is not a question of willpower, but a physiological response reaction.
- Eating speed: Because UPFs[G] are rapidly consumable, hormonal feedback from GLP-1[G]/CCK[G] (10–15 minutes) and leptin rise (15–20 minutes) lag behind eating—fullness arrives late.
How do we intervene?
- Identification: in the Lifestyle Log, separate whole food (NOVA[G] 1-3) from ultra-processed (NOVA[G] 4) sources
- Slow eating: spend at least 15 minutes on a meal so GLP-1[G] and leptin[G] signals arrive on time—conscious chewing, pauses, putting down utensils
- Elimination of liquid calories: sugary drinks cause the fastest metabolic disruption and reward system overstimulation—this is the most effective first step
- Microbiota[G] synergy: reducing UPF[G] and increasing fermentable fiber intake synergistically improve microbiota[G] diversity and SCFA[G] production
What do we measure?
- Hunger scale stability (UPF[G] vs. whole food meals).
- Number of UPF[G]-free meals daily (target: minimum 2).
- Change in intensity of snacking compulsion.
“UPF targets the brain, not satiety. Over-flavoring causes overeating. Natural food provides stable energy.”
Today you don’t need to eliminate anything—just observe. Next to every food in the Lifestyle Log, mark it: whole food (NOVA[G] 1-3) or ultra-processed (NOVA[G] 4). In the evening, look at the proportions.
- In the Lifestyle Log, mark every food: whole food or ultra-processed
- Observe packaged snacks and sugary drinks
- Record eating times
- 20-minute walk after meals
- Mental task: which foods made me hungry again quickly?—note what was in it (fast sugar? little protein? little fiber?)
- At least 2 meals from whole food ingredients (no need to eliminate everything)
- Each meal has a whole food base
- Slow eating: at least 15 minutes per main meal—put down utensil between bites
- Step count at least 7500
- Mental task: look at yesterday’s notes—did UPF[G] appear in the meals that made you hungry quickly? Which whole food meal gave longer satiety?
- Create weekly UPF[G] list and reduction plan
- Protein and fiber in every meal
- Avoidance of liquid calories
- Monitor snacking between meals
- Mental task: when was hunger quieter?—compare the 3-day hunger scales: do you see a difference between UPF[G] days and whole food days?
- body weight;
- meal times and contents (Y–N);
- walk after meals (Y/N);
- snacking (Y/N);
- snack contents (list);
- daily protein intake (g);
- energy density[G] (0/+/++);
- NOVA[G] level;
- sleep quality (1–5);
- hunger scale (1–5);
- stress level (1–5);
- step count;
- bedtime / wake time (AC, AD);
- stool Bristol (1-7);
- bloating;
- flare-up (Y/N);
- daily bowel movements;
- fluid intake (l);
- CGM[G] note (AP, optional);
- UltraBiome dose;
- LOT identifier;
This 3-day period aims to reduce overeating, moderate reward system overload, stabilize insulin response, and provide beneficial nutrient delivery to the microbiota[G].
References
[159] Chassaing B, Koren O, Goodrich JK et al. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature. 2015. Link
In wild-type mice, relatively low concentrations of two ubiquitous emulsifiers — carboxymethylcellulose (CMC) and polysorbate-80 (P80) — induced low-grade inflammation and obesity/metabolic syndrome, and promoted robust colitis in mice predisposed to it. The mucus-protective barrier and microbiota composition were disrupted. The findings implicate dietary emulsifiers, ubiquitous components of processed foods, in the post-mid-20th-century rise in inflammatory bowel disease and metabolic disorders.