Researchers tested what happens when people try to follow a keto diet but mess it up by eating sugar and lots of animal fat together. They fed rats a diet high in ghee (clarified butter) and sugar for 33 days to see what would happen. The rats lost some weight, but their bodies stored more dangerous belly fat, their cholesterol went up, and their immune system showed signs of stress. This study shows that doing keto diet wrong—by mixing sugar with high-fat foods instead of following the real diet rules—might cause health problems even if you lose weight at first.

The Quick Take

  • What they studied: What happens to your body when you try to do a keto diet but keep eating sugar and lots of animal fat at the same time, instead of following the real keto rules
  • Who participated: Male laboratory rats (Wistar strain) divided into two groups: one eating normal rat food and one eating the fake keto diet with sugar and ghee for 33 days
  • Key finding: Rats on the fake keto diet lost overall body weight but gained dangerous belly fat, had higher cholesterol and triglycerides, and showed signs of immune system stress—all without actually entering ketosis (the fat-burning state that real keto aims for)
  • What it means for you: If you’re trying keto diet but still eating sugar and high-fat foods together, you might lose weight on the scale but develop unhealthy fat storage and cholesterol problems. Following the actual keto diet rules (very low sugar, specific fat ratios) appears to be important for real health benefits

The Research Details

Scientists created an experimental diet designed to mimic how people often mess up the keto diet in real life. They divided rats into two groups: one ate normal food, and the other ate a special diet high in ghee (clarified butter) with added sugar. This fake keto diet had about 32% of calories from fat, but not in the right ratio to trigger ketosis—the metabolic state where your body burns fat for energy instead of sugar.

The rats ate their assigned diets for 33 days while researchers measured multiple health markers. They tracked body weight, how much fat accumulated in the belly area, blood cholesterol and triglyceride levels, and immune system markers (special proteins that show inflammation). They also examined liver, kidney, and intestinal tissue under a microscope to look for damage.

This approach allowed researchers to isolate what happens with this specific type of dietary mistake without the complexity of human studies, where people have different genetics, activity levels, and eating habits.

Understanding what goes wrong when people misapply the keto diet is important because many people try keto but don’t follow it correctly. This study creates a clear model of what happens with one common mistake: eating high-fat animal products while still consuming sugar. By using rats, researchers could control every aspect of the diet and measure internal changes that would be difficult to study in humans.

This is an animal study, which means results may not directly apply to humans—rats have different metabolisms and lifespans. The study was relatively short (33 days), so we don’t know about long-term effects. The researchers didn’t specify the exact number of rats used, which makes it harder to evaluate statistical power. However, the study measured multiple health markers and included tissue examination, providing fairly comprehensive data on what happened during this dietary pattern.

What the Results Show

Rats eating the fake keto diet (high ghee and sugar) lost weight overall, but this weight loss came with serious metabolic problems. Instead of losing fat, they actually gained visceral fat—the dangerous type that accumulates around organs in the belly. This is concerning because visceral fat is linked to heart disease and diabetes in humans.

Their blood lipid profiles became unhealthy, with significantly elevated triglycerides (fat in the blood), total cholesterol, and LDL cholesterol (the ‘bad’ kind). The atherogenic index—a measure of heart disease risk—also increased. This suggests the fake keto diet created a metabolic state that increases cardiovascular risk.

The immune system also showed signs of stress. Levels of TNF-α and TGF-β (inflammatory markers) increased, while IL-6 decreased. This pattern suggests the immune system was activated in ways that could promote chronic inflammation. Interestingly, IL-10 (an anti-inflammatory marker) also increased, suggesting the body was trying to balance the inflammatory response.

Tissue examination of the liver, kidneys, and intestines didn’t show major structural damage after 33 days, which is somewhat reassuring. However, the metabolic and immune changes suggest that longer-term damage might develop if this dietary pattern continued. The fact that weight loss occurred without achieving actual ketosis is particularly important—it shows that you can lose weight on the scale while your internal health markers worsen.

Previous research shows that properly done ketogenic diets (very low carb, specific fat-to-protein ratios) can improve metabolic health and reduce inflammation. This study suggests that mixing high animal fat with sugar—a common real-world mistake—produces opposite effects: weight loss on the scale but metabolic dysfunction underneath. The findings align with research showing that high-sugar, high-fat combinations are particularly problematic for metabolic health.

This study used rats, not humans, so results may not directly translate to people. The study lasted only 33 days, which is relatively short for understanding long-term health effects. The researchers didn’t specify how many rats were in each group, making it difficult to assess statistical reliability. The diet was designed to mimic one specific type of keto diet mistake; other common mistakes might produce different results. Additionally, rats have faster metabolisms than humans, so the timeline for developing problems might be different in people.

The Bottom Line

If you’re considering a ketogenic diet, follow the actual diet guidelines carefully rather than trying a modified version with added sugar and high animal fat. The evidence from this study suggests (moderate confidence) that this combination creates metabolic problems despite initial weight loss. Consult with a healthcare provider or registered dietitian before starting any restrictive diet to ensure you’re doing it correctly.

Anyone considering trying a keto diet should pay attention to this research, especially if they’ve been tempted to ‘cheat’ by adding sugar while eating high-fat foods. People with heart disease risk factors, high cholesterol, or metabolic issues should be particularly careful about diet quality, not just weight loss. However, this study doesn’t directly apply to people following a properly-formulated ketogenic diet with appropriate macronutrient ratios.

In this rat study, metabolic and immune changes appeared within 33 days. In humans, similar changes might take weeks to months depending on individual factors. Weight loss might appear quickly (within days to weeks), but the unhealthy metabolic changes could develop gradually without obvious symptoms, which is why blood work and health monitoring are important.

Want to Apply This Research?

  • If following a keto diet, track your macronutrient ratios daily (fat, protein, carbohydrate percentages) to ensure you’re staying within proper ketogenic ranges, not just reducing calories. Log added sugars separately to catch hidden sugar intake that could derail the diet’s benefits.
  • Use the app to set a daily carbohydrate limit (typically under 50g for keto) and receive alerts when you approach it. Create a ‘keto-approved foods’ list to avoid the temptation of mixing high-fat foods with sugar. Set reminders to review your macronutrient ratios weekly to catch drift from the actual diet plan.
  • Track weight weekly but also monitor how you feel (energy, digestion, mood) and plan for regular blood work (cholesterol, triglycerides, glucose) every 3-6 months if following keto long-term. Use the app to record these lab results and identify patterns between your diet adherence and health markers.

This study was conducted in rats and may not directly apply to humans. The findings suggest potential risks with improperly-followed ketogenic diets, but individual responses vary based on genetics, overall diet quality, exercise, and health status. Before starting any restrictive diet, including ketogenic diets, consult with your healthcare provider or a registered dietitian nutritionist. This research should not replace professional medical advice. If you have existing health conditions, take medications, or have concerns about your metabolic health, seek personalized guidance from qualified healthcare professionals before making significant dietary changes.