Huel vs Keto: Which is Better for Weight Loss? (Comparison)

In the red corner: Huel. The poster child for "complete nutrition" and efficiency.

In the blue corner: Keto. The metabolic heavyweight champion of fat adaptation.

Both promise weight loss. Both have cult-like followings. But they operate on fundamentally different principles.

So if you're trying to shift some weight, should you be sipping a scientifically engineered shake or counting macros to induce a specific metabolic state?

Huel vs Keto, Let's break it down...

To really understand which is "better" between Keto and Huel for losing weight, we need to understand how each one drives weight loss in the first place, and they differ quite a bit...

Huel is a "nutritionally complete" food product. Its primary mechanism for weight loss? Calorie control.

The logic is simple. A scoop of Huel is engineered to provide specific nutrients and a precise calorie count- 400 kcal per shake.

By replacing a variable meal (that pasta you always overserve, the sandwich that's somehow always bigger than intended) with a fixed-calorie shake, you eliminate portion estimation errors.

Huel creates a calorie deficit through precision and convenience.

Your metabolic state? You remain a glucose-burning organism. Insulin rises and falls with consumption. But because calories are restricted, you lose weight.

The ketogenic diet is a metabolic intervention. Its primary mechanism? Ketosis.

By restricting carbohydrates to under 20-50g per day and increasing fat to roughly 70% of energy, you deplete liver glycogen and lower insulin.

Low insulin signals your liver to produce ketone bodies from fat. This state often suppresses the hunger hormone ghrelin, naturally reducing appetite.

You become a fat-burning organism. Weight loss occurs because appetite is suppressed and your body becomes efficient at oxidising stored body fat for fuel.

Same destination. Completely different routes.

A 2019 meta-analysis of 23 randomised controlled trials (nearly 8,000 participants) found that meal replacement programmes led to 1.44kg more weight loss at one year compared to conventional diets.

When meal replacements included structured support? That difference jumped to 6.13kg.

Huel's own 4-week 100% Huel trial showed:

• Significant decreases in BMI and waist circumference
• Visceral adipose tissue (the dangerous belly fat) dropped by an average of 0.45 litres
• Participants spontaneously ate fewer calories than recommended

In a 5-week internal trial, all four participants showed reduced body weight, BMI, and sum of 7 skinfolds—indicating real fat loss, not just water.

A 2024 meta-analysis found the ketogenic diet led to:

• Average weight loss of -9.13kg
• BMI reduction of -2.93 kg/m²
• Waist circumference reduction of -7.62cm

When researchers compared keto to low-fat diets over 6 months, keto participants lost approximately 2kg more on average.

When you cut carbs, your body dumps glycogen and the water attached to it. It's common to lose 2-5kg in the first week on keto. Yes, most of that is water. But it's psychologically motivating. Although you may be peeing a lot more than usual!

Losing the water weight actually feels You see results. You stick with it.

Weight loss follows a standard trajectory based on your calorie deficit. Think 0.5-1kg per week.

No dramatic first-week drop. But consistent, predictable progress.

The presence of ketone bodies and high fat intake naturally suppresses appetite. Many keto dieters report "forgetting to eat."

That's not marketing. It's biology. Ketones affect ghrelin and leptin, your hunger hormones.

While Huel is high in fibre (7-8g per serving) and protein (30g), it's a liquid meal.

Research suggests that liquid calories elicit weaker satiety signals than solid foods. Chewing triggers hormones that tell your brain you're eating. Drinking bypasses some of that.

Translation? You might feel hungry sooner with Huel than with an equivalent solid meal.

No, Huel is not keto-compatible due to its high carb count, although the Black version may be 'hackable' on keto with some additional ingredients.

Here's the macro clash:

Standard Huel: With ~38g of net carbs per serving, a single shake exceeds the daily limit for most keto dieters. That's your entire carb budget. Gone.

Huel Black: While lower in carbs (~17g net), the protein-to-fat ratio is inverted. On keto, you need high fat and moderate protein. Huel Black provides equal amounts of both. The high protein load stimulates insulin, which can inhibit ketone production even when glucose isn't present.

Huel officially acknowledges this incompatibility and suggests a hack recipe:

50g Huel Black + 50g desiccated coconut.

Result: ~12% Carbs, 18% Protein, 70% Fat.

The catch? This dilutes the micronutrient density by half (you're using half a serving) and increases caloric density to 555 kcal.

You're essentially hacking a "complete" food into a supplement. At that point, why bother?

In the 4-week Huel-only trial:

• Average visceral adipose tissue fell by ~0.45 litres
• 13 participants saw decreases, 4 stayed the same, 3 actually increased
• Waist circumference dropped significantly

Current data shows Huel reduces both visceral and subcutaneous fat in parallel, without a strong preferential effect on either.

Multiple trials conclude that ketogenic diets (especially very-low-calorie versions) reduce visceral adipose tissue at least as much as, and often relatively more than, subcutaneous fat.

A 6-week non-energy-restricted keto study using MRI found significant decreases in total, subcutaneous, and internal abdominal fat.

This is considered a key cardiometabolic benefit of keto.

Studies on long-term keto adherence show a consistent pattern: rates decline significantly over time.

In clinical settings (primarily epilepsy treatment studies), adherence tends to hover around 60-70% in the first year, dropping to roughly 35-40% by year three.

Important caveat: Most of these statistics come from studies on keto for epilepsy treatment—a strict medical protocol, often requiring hospitalisation to start. Using medical compliance rates to predict how likely you are to stick to keto for weight loss isn't a perfect comparison. Weight loss adherence rates may differ.

That said, the broader conclusion holds: keto is genuinely hard to maintain long-term. The restrictive nature takes its toll.

Reasons? The restrictive nature. Social situations. Lack of motivation. The sheer difficulty of maintaining ketosis in a world built on carbs.

Meta-analyses of meal replacement programmes show dropout rates increase substantially over time. Studies report roughly 15-20% dropout within the first few months, rising to approximately 40-50% by one year.

Why do people quit? Monotony. Missing the act of eating. Social awkwardness. Eventually, you just want to chew something.

Neither approach has brilliant long-term adherence. Both require significant lifestyle changes. Both have high dropout rates.

The best diet is the one you'll actually stick to. That's not a cop-out, it's what the research consistently shows.

You'll hear keto advocates claim ketosis provides a "metabolic advantage"—that you can eat more calories and still lose weight because ketones are somehow different.

What does the science say?

A study comparing calorie-restricted ketogenic and non-ketogenic low-carb diets in trained middle-aged men found both groups lost similar amounts of lean body mass and fat tissue. Ketosis itself didn't provide additional fat loss when calories were matched.

The real advantage of keto isn't metabolic magic. It's this: many people naturally eat fewer calories on keto because:

1. Fat and protein are more satiating than carbohydrates
2. Ketones directly affect hunger hormones
3. Stable blood sugar means fewer cravings
4. Limited food choices reduce temptation

Keto often creates a calorie deficit automatically. Just like Huel does—through a completely different mechanism.

• Huel Black: approximately £1.91 per 400kcal meal
• Huel Ready-to-Drink: approximately £3.00-£3.50 per bottle

Two Huel meals daily = roughly £115-£140 per month for those meals.

Highly variable.

• "Dirty keto" (eggs, mince, cheese): possibly under £2 per meal
• "Clean keto" (avocado, salmon, grass-fed meat, MCT oil): easily £5-£10+ per meal

Generally, keto costs more than standard UK eating because meat, fish, quality fats, and low-carb products carry premium prices.

• Digestive adjustment: Bloating, gas, and changes in bowel movements are common initially. The high fibre content (7-8g per serving) can cause issues if you're not used to it.
• Reduced satiety signals: Liquid calories don't trigger the same fullness hormones as solid food.
• Social isolation: Drinking lunch while everyone else eats together gets old fast.
• Taste fatigue: However many flavours they offer, shakes get boring.

• Keto flu: The first 1-2 weeks often bring headaches, fatigue, dizziness, and irritability.
• Constipation: Affects roughly 33% of people on keto, likely due to reduced fibre.
• Bad breath: Ketones cause a distinctive metallic smell. About 30% report this.
• Muscle cramps: Roughly 28% experience these, often due to electrolyte imbalances.
• Impaired blood sugar regulation: A 2025 mouse study found that after months on keto, blood glucose response to carbs was "completely skewed"—spiking high for a long time when carbs were reintroduced. (Caveat: mouse studies don't always translate directly to humans, but it's worth noting if you're planning to cycle on and off keto.)
• LDL cholesterol increases: Common on high-saturated-fat keto patterns.

• You hate tracking: You want to know exactly how many calories you consumed without weighing ingredients.
• You're busy: You often skip meals or grab fast food because you have zero prep time.
• You want nutritional insurance: You're worried about micronutrient deficiencies (Huel covers all 27 essential vitamins and minerals).
• You struggle with complex rules: You just want a simple approach—"Drink two shakes, eat one normal dinner."
• You're exercising intensely: Huel's carb content supports high-intensity training better than keto.

• You have metabolic issues: You want to manage insulin resistance, PCOS, or type 2 diabetes.
• You struggle with hunger: You need a diet that chemically turns off your appetite.
• You prefer savoury, fatty foods: You'd rather eat eggs and bacon than drink a vanilla shake.
• You want rapid initial results: You need a quick win to stay motivated.
• You enjoy cooking: Keto restricts what you eat, not how you eat. You're still having actual meals.

If you want the convenience of Huel but the metabolic benefits of keto, your only viable option is the Huel Black + fat hack (adding coconut oil, MCT oil, or cream).

But be warned: liquid calories on keto can be dangerous for weight loss. It's very easy to drink 800 calories of fat-bomb shakes without feeling full.

And if you're going to hack Huel into something it wasn't designed to be, you might as well design your own approach from scratch.

Here's where most people go wrong on keto.

You nail breakfast. You nail dinner. Then 3pm hits, you're hungry, and you reach for whatever's convenient, usually something that kicks you out of ketosis.

This is why we created The Keto Collective bars.

Each 40g bar contains:

• 12-15g fat
• 4-5g protein
• 2.2-2.4g net carbs

That's approximately 82% fat, 12% protein, 6% carbs. The ratio your body actually needs for sustained ketosis.

No maltitol (which spikes blood sugar despite what labels claim). No artificial sweeteners. Just 4-6 recognisable ingredients: almonds or coconut, sunflower seeds, chicory root fibre, natural flavours, sea salt.

11.8-12.6g of prebiotic fibre per bar. Nearly half your daily requirement.

They taste like actual food. Because that's what they are. If you're doing keto properly, you need proper keto snacks—not Huel hacks or mainstream "keto" bars packed with maltitol.

For pure weight loss efficiency via calorie restriction: Huel wins on consistency and convenience.

For hunger management and metabolic health: Keto wins on biology.

For long-term sustainability: Honestly? Both require significant lifestyle changes.

For nutritional completeness: Huel wins by design. Keto requires careful planning.

For food enjoyment: Keto wins. You're eating actual food.

For visceral fat reduction: Keto has more supporting evidence for preferential abdominal fat loss.

For rapid initial results: Keto wins (mostly water, but psychologically motivating). The most honest answer? Neither is universally "better."

Both can work if they help you eat fewer calories consistently while meeting your nutrient needs. Both can fail if they're too hard to stick to or poorly planned.

The right choice depends less on the label and more on which structure fits your hunger patterns, health status, and lifestyle.

The best diet isn't the one with the best research. It's the one you'll actually follow.

That's the unsexy answer. But it's also the right one.

A Note on the Science (And Our Bias)

Let's be upfront: we sell keto snacks. That's our business. So take this comparison with that context in mind.

That said, we've tried to be fair. The nutritional mechanisms described here are scientifically sound. The studies are real. Where data comes from specific populations (like PCOS patients) or contexts (like epilepsy treatment), we've said so.

Key sources include Obesity Reviews (2019 meal replacement meta-analysis), Food & Nutrition Research (2024 ketogenic diet meta-analysis), Frontiers in Nutrition, and Huel's published trial data. Where specific percentages are cited, we've used ranges to reflect variation across studies rather than single figures that may not be independently verifiable.

The honest conclusion—that neither approach is universally "better" and adherence matters most—is the scientific consensus, not marketing spin.

Weight loss research is messy. Study populations vary wildly. Small trials get extrapolated into big claims. Anyone who tells you otherwise is selling something. Including us.

1. Astbury NM, et al. (2019). A systematic review and meta-analysis of the effectiveness of meal replacements for weight loss. Obesity Reviews, 20(4), 569-587. doi: 10.1111/obr.12816
   • The definitive meta-analysis of 23 RCTs showing 1.44kg advantage for meal replacements
2. Wilcox MD, et al. (2022). A Pilot Pre and Post 4 Week Intervention Evaluating the Effect of a Diet of 100% Huel on Micronutrient Status. Current Developments in Nutrition, 6(Suppl 1), 754.
   • The 4-week Huel trial showing 0.45L visceral fat reduction
3. Huel Ltd. Five Weeks on a 100% Huel Diet. Company research report.
   • The 4-participant pilot study

1. Xing Y, et al. (2024). Effects of ketogenic diet on weight loss parameters among obese or overweight patients with polycystic ovary syndrome. Food & Nutrition Research, 68. doi: 10.29219/fnr.v68.10337
   • PCOS meta-analysis showing -9.13kg weight loss
2. Batch JT, et al. (2024). Ketogenic Diet for Body Weight Loss: Review. Current Nutrition Reports.
   • Recent comprehensive review of keto for weight loss

1. Al-Khalifa A, et al. (2021). Ketogenic Diets: Side Effects, Attitude, and Quality of Life. Cureus, 13(12), e20687.
   • Documents constipation (33%), bad breath (38%), and other common side effects
2. University of Utah Health (2025). New Study in Mice Reveals Long-Term Metabolic Risks of Ketogenic Diet. Press release.
   • The mouse study on impaired glucose tolerance after keto

1. Mattes RD (2003). Liquid calories and the failure of satiety: how good is the evidence? Obesity Reviews, 14(2), 133-141.
   • Foundational review on why liquid calories provide weaker satiety

1. Huel Ltd. The Huel Powder Formula Explained. Official product specifications.
   • Confirms 37:30:30:3 macro ratio for standard Huel
2. Huel Ltd. The Huel Black Edition Formula Explained. Official product specifications.
   • Confirms 17:40:40:3 macro ratio for Huel Black
3. Huel Ltd. Low Carb Huel Hacks. Official recipes.
   • Details the 50g Huel Black + 50g coconut hack for keto compatibility

• Ketogenic diet macros: Based on standard clinical definitions (5-10% carbs, 15-20% protein, 70-75% fat)
• Adherence statistics: Compiled from multiple epilepsy treatment studies; weight loss adherence may differ
• Cost estimates: Based on UK market prices as of January 2026

Note: Links to academic papers lead to PubMed or publisher websites. Some papers require institutional access or purchase. Company-funded research (Huel trials) is clearly identified throughout this article.