LeptiThin Max Reviews 2026: BHB Supplement Buyer's Guide
Long-form consumer overview details the LeptiThin Max BHB + MCT formula, outlines key safety considerations and realistic expectations, and summarizes purchasing policies consumers should verify directly before ordering.
Disclaimer: This article contains affiliate links. If you purchase through these links, a commission may be earned at no additional cost to you. This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any new supplement. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease.
CHICAGO, January 7, 2026 (Newswire.com) - LeptiThin Max Explained: Ingredient Breakdown and What to Know About BHB Ketone Supplements
Why You're Here (And Why That's Actually Smart)
It's January 2026. You just saw an ad for LeptiThin Max-probably on Facebook, Instagram, or YouTube-and something about it made you pause. Maybe it was a claim about ketosis support or appetite changes. Maybe it was the idea of ketone supplementation without strict carb restriction.
So you did what thoughtful consumers do: you Googled it.
That research instinct serves you well. The supplement space is crowded, and the only way to make a decision you'll feel good about is to understand what you're actually considering-the ingredients, the company claims, and whether it genuinely fits your situation.
This guide gives you the information you need to evaluate LeptiThin Max on your own terms. We'll cover what's in the formula, what ingredient-level research exists, who might find this type of supplement worth exploring, who should look elsewhere, and how to think about realistic timelines.
No pressure. Just clarity.
See current LeptiThin Max pricing and details (verify pricing at checkout)
Table of Contents
What Is LeptiThin Max?
Understanding BHB: What the Ingredient Research Shows
Complete Ingredient Breakdown
Who Might Consider This Type of Supplement
Who Should Explore Other Options
The January Context: A Note on Resolution Season
How LeptiThin Max Compares to Other Approaches
Setting Realistic Expectations
Usage Guidelines
Pricing, Packages, and Refund Policy
Frequently Asked Questions
Final Assessment
Part 1: What Is LeptiThin Max?
LeptiThin Max is a dietary supplement combining multiple forms of Beta-Hydroxybutyrate (BHB) with MCT powder. According to the company, it's marketed as an exogenous ketone supplement designed to raise blood ketone levels and support a ketogenic-style routine.
What's in the Formula
Per the product information, LeptiThin Max contains:
MCT Powder (Medium-Chain Triglycerides)
Magnesium Beta-Hydroxybutyrate
Calcium Beta-Hydroxybutyrate
Sodium Beta-Hydroxybutyrate
Manufacturing Information
According to the company, LeptiThin Max is made in the USA and manufactured in a GMP-certified facility.
Important note: FDA does not "approve" dietary supplements before they are sold, and facility-related language should not be interpreted as product approval. Dietary supplements are regulated differently than medications.
Important Clarifications
Before going further, here's what this product is and isn't:
It's a dietary supplement - not a medication
Dietary supplements do not require FDA premarket approval - the FDA does not evaluate supplements for effectiveness before they are sold
It has not been independently clinically studied as a finished product
Individual responses vary - some people may notice effects, others may not
It's not a replacement for medical care - if you have health concerns, work with your doctor
These aren't negatives unique to this product-they apply to the entire dietary supplement category. But they're worth understanding before you make any decision.
Part 2: Understanding BHB - What the Ingredient Research Shows
To evaluate any BHB supplement, it helps to understand what ketones are and what research exists at the ingredient level.
Your Body's Fuel Options
Your body can use two primary fuel sources:
Glucose (from carbohydrates) - The default fuel for most people eating standard diets
Ketones (from fat metabolism) - An alternative fuel that becomes available when carbs are limited
When carbohydrate intake drops significantly, your liver produces ketone bodies-including Beta-Hydroxybutyrate (BHB)-from stored fat. This metabolic state is called ketosis.
The Traditional Ketogenic Approach
Ketogenic dieting achieves ketosis through extreme carbohydrate restriction (typically under 20-50 grams daily). Research has examined this approach extensively.
However, many people find strict keto difficult to maintain because:
The restriction is significant
Social eating becomes complicated
A single high-carb meal can disrupt the process
The adjustment period can be uncomfortable
The Exogenous Ketone Concept
"Exogenous" means "from outside the body." BHB supplements provide ketone bodies you consume rather than produce through dietary restriction.
The concept: if you provide ketones directly, your body may have access to elevated ketone levels without the dietary requirements.
What Ingredient-Level Research Shows
Important context: The following discusses research on BHB and related compounds as ingredients. This research does not pertain to LeptiThin Max as a specific finished product, which has not been independently clinically studied.
Blood Ketone Levels: Studies confirm that oral BHB supplementation can elevate blood ketone concentrations. Research published in peer-reviewed journals has measured this effect across various study populations.
Appetite Research: Some studies have explored whether elevated ketones influence hunger signals. Research in this area has shown varied results-some participants reported changes in appetite, while others did not. Individual responses appear to differ considerably.
The Important Caveat: Elevated ketones from supplementation do not automatically produce the same effects as ketones generated through dietary carbohydrate restriction. The body's metabolic response involves many factors beyond ketone levels alone.
The Honest Summary: BHB is a compound with measurable effects on blood ketone concentrations. However, how this translates to individual experiences varies significantly from person to person. Weight outcomes are not established for this finished product, and the supplement category as a whole lacks the extensive clinical trial data that prescription medications undergo.
Part 3: Complete Ingredient Breakdown
Here's what's in the LeptiThin Max formula based on available information, along with what ingredient-level research suggests.
MCT Powder (Medium-Chain Triglycerides)
What it is: MCT powder derives from fatty acids in coconut and palm kernel oils. Unlike most dietary fats, MCTs are metabolized differently-they travel directly to the liver where they can be converted to ketones.
What research suggests: Studies have examined MCT consumption in various contexts. Some research has found associations between MCT intake and changes in satiety compared to other fat sources. Results have varied across studies.
Practical note: MCT is one of the more researched compounds in this category, though findings vary and should not be interpreted as guarantees for any specific product.
Magnesium Beta-Hydroxybutyrate
What it is: BHB bonded to magnesium, an essential mineral involved in numerous bodily processes.
What research suggests: Magnesium plays roles in energy production, muscle function, nerve function, and various metabolic processes. Many adults have suboptimal magnesium intake.
Consideration: People with kidney concerns should consult their healthcare provider before taking magnesium supplements.
Calcium Beta-Hydroxybutyrate
What it is: BHB bonded to calcium, a mineral important for bone health and various cellular functions.
What research suggests: Calcium's role in bone health is well-documented. Its relationship to other health outcomes is more complex and varies by individual.
Consideration: Calcium can interact with certain medications, including some antibiotics and thyroid medications.
Sodium Beta-Hydroxybutyrate
What it is: BHB bonded to sodium, an essential electrolyte.
What research suggests: Sodium BHB is commonly used in exogenous ketone research. Studies confirm it can raise blood ketone levels, though how individuals respond to elevated ketones varies.
Important consideration: Each serving of BHB salts contains sodium. People on sodium-restricted diets, those with blood pressure concerns, or those taking certain medications should consult their healthcare provider before use.
Formulation Context
The combination of multiple BHB salt forms with MCT is typical of this supplement category. Different salt forms provide varied mineral content and may affect absorption and tolerability differently.
These observations describe the ingredient category generally. They do not constitute claims about the specific LeptiThin Max formula's effects.
Part 4: Who Might Consider This Type of Supplement
Rather than making promises about who will benefit, this section helps you assess whether exploring a BHB supplement makes sense for your situation.
This Category of Supplement May Be Worth Exploring If You:
Have interest in ketone supplementation without strict dietary restriction:
If you're curious about exogenous ketones but find extreme carb restriction unrealistic for your lifestyle, BHB supplements offer a different approach. This doesn't mean the supplement replaces healthy eating-it means you're not required to eliminate food groups to try this category.
Are making broader lifestyle improvements:
Supplements are sometimes used as one component of a larger approach. If you're already working on nutrition, activity, sleep, and stress management, a supplement might fit as an additional element. If you're hoping a supplement will produce changes while everything else stays the same, expectations should be adjusted accordingly.
Understand that individual responses vary:
Some people who try BHB supplements report positive experiences. Others notice little difference. If you can approach this with curiosity rather than expectation-willing to assess your personal response over adequate time-you're positioned for a clearer evaluation.
Are comfortable with the commitment required for fair assessment:
Meaningful evaluation requires consistent use over time (typically 60-90 days minimum). Short trials with high expectations often lead to disappointment regardless of the product.
A Note for Women Navigating Midlife Changes
If you're a woman over 40 experiencing changes in how your body responds to diet and exercise, you're not imagining it. Hormonal shifts during perimenopause and menopause genuinely affect metabolism.
Some women in this demographic explore BHB supplements as one option among many. However, this is also a demographic where working with a healthcare provider is particularly valuable. Hormonal, cardiovascular, and other factors deserve professional consideration.
The January Context
If you're reading this as part of a New Year's resolution, here's what serves you best:
Your goals are more likely to succeed with:
Sustainable approaches rather than extreme ones
Realistic timelines measured in months
Multiple progress indicators beyond just the scale
Systems and habits rather than pure willpower
Plans for when initial motivation fades
A supplement can be part of this approach. It cannot be the entire approach.
Check current LeptiThin Max availability (verify pricing at checkout)
Part 5: Who Should Explore Other Options
Honest guidance means being clear about who this type of product likely doesn't serve.
This Type of Supplement May Not Be Appropriate If You:
Expect significant changes without other modifications:
If you're looking for something that produces major changes while your eating, activity, and lifestyle patterns remain unchanged, supplements generally won't meet those expectations. This applies to all supplements, not just this one.
Have health conditions requiring medical supervision:
People with the following should NOT use BHB supplements without explicit healthcare provider approval:
Diabetes (type 1 or type 2)
Kidney disease or concerns
Heart conditions
Blood pressure issues
Liver concerns
Eating disorders (current or history)
Any condition affecting electrolyte balance
The BHB salts contain sodium, magnesium, and calcium, which can interact with various health conditions and medications.
Are pregnant or breastfeeding:
Research on exogenous ketone supplementation during pregnancy or breastfeeding is insufficient. The appropriate choice is to avoid these supplements during these periods or use them only under direct medical supervision.
Take medications that affect electrolyte balance:
This includes diuretics, blood pressure medications, heart medications, certain diabetes medications, lithium, and some antibiotics. Consult your pharmacist or doctor about potential interactions.
Have a history of eating disorders:
Products marketed around weight management can trigger unhealthy patterns for people with eating disorder histories. Professional support should guide any decisions in this context.
Are under 18:
Weight management supplements are not appropriate for minors.
Are seeking prescription-level interventions:
GLP-1 medications (like Ozempic, Wegovy, or Mounjaro) and BHB supplements work through fundamentally different mechanisms. They should not be compared as alternatives. If you're interested in prescription options, that's a conversation for your healthcare provider.
If You Feel Like Nothing Works
If you've tried many approaches and feel like nothing produces results, a supplement is unlikely to be your missing piece. This feeling often indicates:
Underlying factors worth investigating with a doctor
Previous approaches not sustained long enough
Unrealistic timelines or expectations
Contributing factors beyond diet (sleep, stress, medications, medical conditions)
If you prefer evidence-based approaches with stronger data, prescription therapy and lifestyle interventions under professional guidance typically have more research support than supplements.
Part 6: The January Context - A Note on Resolution Season
You're likely reading this during peak resolution season. That timing matters.
What's Happening Right Now
January represents the highest-intent period for wellness products. The emotional landscape includes post-holiday awareness, fresh determination, and significant advertising exposure.
The Pattern Worth Recognizing
Many people experience a familiar cycle: high initial motivation, gradual decline, eventual abandonment, and lingering frustration. This pattern isn't about personal failure-it's about unsustainable approaches meeting predictable psychology.
What Research Suggests About Sustained Change
Studies on sustained behavior change consistently show:
Moderate, maintainable changes outperform extreme approaches
Support systems and accountability matter
Environmental design beats willpower
Self-compassion predicts better outcomes than perfectionism
Small wins compound over time
Where Supplements Fit
A supplement can be part of a thoughtful approach if you:
View it as one component, not the solution
Combine it with genuine lifestyle attention
Commit to adequate evaluation time
Maintain perspective regardless of outcome
A supplement becomes counterproductive if you:
Use it to avoid other changes
Expect it to work independently
Abandon all effort if it disappoints
Let purchasing become a substitute for action
Part 7: How LeptiThin Max Compares to Other Approaches
Understanding your options helps you make informed decisions.
BHB Supplements vs. Ketogenic Dieting
Approach
Ketogenic Diet: Produces ketones through carb restriction
BHB Supplements: Provides ketones directly
Dietary Requirements
Ketogenic Diet: Requires significant restriction
BHB Supplements: More flexible
Research Depth
Ketogenic Diet: Extensive research on dietary ketosis
BHB Supplements: More limited research on exogenous ketones
Sustainability
Ketogenic Diet: Can be challenging for many people
BHB Supplements: Often easier to maintain as part of a routine
Individual Variation
Ketogenic Diet: Significant variation between individuals
BHB Supplements: Significant variation between individuals
Neither approach is universally superior. Dietary ketosis has more research but requires restriction most people find difficult to sustain. Exogenous ketones offer flexibility but have less outcome-specific research.
BHB Supplements vs. Other BHB Supplements
The BHB supplement market includes many options with similar formulations. Most contain BHB salts (often multiple forms) and frequently include MCT.
Differences between products often come down to:
Manufacturing practices (hard for consumers to verify)
Customer service experience
Return policy handling
Price point
LeptiThin Max appears to offer a formulation typical of this category at a competitive price point with a refund policy.
BHB Supplements vs. Prescription Options
BHB supplements and prescription medications like GLP-1 drugs work through fundamentally different mechanisms. They are not comparable alternatives.
Mechanism
GLP-1 Medications: Affects hormones involved in appetite and blood sugar
BHB Supplements: Raises blood ketone levels
Access
GLP-1 Medications: Prescription required
BHB Supplements: Over-the-counter
Research
GLP-1 Medications: Extensive clinical trials
BHB Supplements: Limited product-specific research
Cost
GLP-1 Medications: Significantly higher
BHB Supplements: Lower
If you're interested in prescription approaches, discuss that with your healthcare provider. A supplement doesn't address what prescription medications address.
Supplements vs. Lifestyle Changes Alone
Most people can work toward their goals through sustained lifestyle attention without any supplements. The fundamentals-nutrition, activity, sleep, stress management-are more foundational than any product.
Where supplements sometimes fit:
As a routine that reinforces daily focus
As one element within a broader approach
Where supplements don't fit:
As replacements for fundamentals
As solutions that work independently
View current LeptiThin Max options (verify pricing at checkout)
Part 8: Setting Realistic Expectations
Unrealistic expectations are the primary reason people feel disappointed by products that might have provided modest support with appropriate expectations.
What Some People Report
Based on general patterns with BHB supplementation (these are not guarantees, predictions, or typical results; no typical results data is available for this finished product):
Early period (Days 1-14): Some users report noticing changes in energy or appetite. Others notice nothing initially. Both experiences are normal. Mild digestive adjustment is possible as your body adapts to the formula.
Weeks 2-4: If the supplement is interacting with your body's processes, subtle patterns may emerge. This is still early for any meaningful assessment.
Weeks 4-8: Trends may become clearer for some users. Others may remain uncertain about effects.
Weeks 8-12: This timeframe allows for more meaningful evaluation. Patterns should be apparent enough to inform whether continuing makes sense for you.
What NOT to Expect
Remove these expectations explicitly:
Rapid, dramatic changes - Supplements don't produce these
Changes without any other attention - Supplements don't work in isolation
Identical responses to anyone else - Your body is unique
Permanent effects from temporary use - Sustained habits produce sustained outcomes
Weight loss guarantees - Weight outcomes are not established for this product
Better Progress Indicators
Don't rely solely on any single measure. Consider:
How you generally feel day-to-day
Energy patterns
Appetite observations
How clothes fit
Physical capacity
Sleep quality
If tracking with your doctor: relevant markers
Part 9: Usage Guidelines
If you decide to try LeptiThin Max, here's how to approach it.
Basic Usage
According to the company, the recommendation is one capsule with each meal.
Supporting Factors
While no specific diet is required, consider:
Emphasizing whole foods when possible
Staying adequately hydrated
Maintaining regular physical activity
Prioritizing sleep quality
Managing stress where you can
These factors matter regardless of supplementation.
Assessment Approach
Consider keeping simple notes:
Did you take the supplement consistently?
Any observations about energy, appetite, or how you feel?
Any concerns or reactions?
This documentation helps you evaluate objectively rather than relying on memory.
Timeline for Evaluation
At 30 days: Initial check-in. Any observations? Any concerns worth addressing?
At 60 days: Within refund window. Preliminary assessment of whether continuing makes sense.
At 90 days: Adequate time for meaningful evaluation. Decide whether to continue based on your actual experience.
Part 10: Pricing, Packages, and Refund Policy
Pricing Information
According to the official LeptiThin Max website, pricing varies by package size. Multi-bottle packages typically cost less per bottle and may include free shipping. Single bottles may include a shipping fee.
Pricing can change. Always verify current pricing on the official website before ordering.
Package Considerations
Single bottle: Minimal commitment, higher per-bottle cost, may not provide adequate evaluation time.
Multi-bottle packages: Better per-bottle value, adequate time for fair assessment, larger upfront commitment.
For first-time users, consider whether the evaluation timeline aligns with the refund window.
The 60-Day Refund Policy
According to the company:
Timeline: 60 days from purchase
Condition: Bottle must be returned (open or unopened)
Shipping: Customer responsible for return shipping costs
Process: Contact support to initiate
Return Address (per company information): Attn: Returns Jetpack Shipping 285 Northeast Ave. Tallmadge, Ohio 44278, USA
Verify current refund terms on the official website, as policies may be updated.
Payment Processing
According to the company's FAQ, charges appear from BuyGoods Inc. on your statement.
See current LeptiThin Max pricing (verify at checkout)
Part 11: Frequently Asked Questions
Product Questions
How much should I order?
According to the company, they suggest consistent use for 60-90 days. Multi-bottle packages align with this timeframe and offer better per-bottle pricing. Single bottles work for testing tolerance with minimal commitment, though one month may not provide adequate evaluation time.
Is LeptiThin Max safe?
According to the company, the formula is vegetarian, gluten-free, and non-GMO, made in the USA in a GMP-certified facility. However, supplements may not be suitable for everyone.
Discuss with a healthcare provider before use if you:
Have any chronic health conditions
Take prescription medications
Are pregnant or breastfeeding
Have kidney, liver, or heart concerns
Have blood pressure issues (sodium content is relevant)
What are potential side effects?
Based on general patterns with BHB supplementation:
Possible for some users:
Initial digestive adjustment
Changes in thirst or hydration needs
Electrolyte effects in sensitive individuals
If you experience persistent concerns, discontinue use and consult your healthcare provider.
Will this work for me?
There's no way to predict how any individual will respond to any supplement. Research on BHB supplementation shows varied responses-some people report positive experiences, others notice little difference. Weight outcomes are not established for this finished product.
The refund policy exists because the company recognizes individual variation.
How quickly will I receive my order?
According to the company:
US/Canada: 5-7 business days via major carriers
International: 8-15 business days depending on customs
Is this a subscription?
According to the company, this is a one-time purchase. No auto-ship, no recurring billing.
Where is LeptiThin Max available?
According to the company, it's sold exclusively through their official website-not through Amazon, Walmart, or retail stores.
Comparison Questions
How does this compare to other BHB supplements?
Most BHB supplements contain similar core ingredients. Differences typically involve manufacturing practices, customer service, and return policy experience rather than dramatic formula variations.
Is this like prescription options?
No. BHB supplements and prescription medications work through different mechanisms and should not be compared. If you're interested in prescription approaches, discuss that with your healthcare provider.
Is this better than dietary changes alone?
Dietary changes, activity, sleep, and stress management are more foundational than any supplement. A supplement might fit as one element within a broader approach, not as a replacement for fundamentals.
Results Questions
How long until I notice something?
Individual timelines vary considerably. Some people report noticing energy or appetite changes within the first few weeks. Others require longer or don't notice changes. A fair evaluation typically requires 60-90 days of consistent use.
What if I don't notice anything?
If you've used the product consistently for 60 days and notice nothing:
Consider using the refund policy
Recognize this product may not produce noticeable effects for your body
Consider consulting a healthcare provider about other approaches
Not every product produces noticeable effects for every person.
Part 13: Final Assessment
After examining the ingredients, available research, company information, and realistic expectations, here's a balanced evaluation:
What LeptiThin Max Offers
A BHB supplement in an established category: BHB and MCT are compounds with research at the ingredient level. This is a real category of supplementation, though individual responses and weight outcomes vary significantly and are not established for finished products.
Flexibility positioning: For people who can't sustain strict ketogenic dieting but are curious about ketone supplementation, exogenous ketone supplements offer a different approach.
A refund policy: The 60-day refund policy allows evaluation before the investment becomes final.
A formulation typical of this category: The ingredient combination is consistent with other products in this space.
What to Consider Carefully
No product-specific clinical studies: LeptiThin Max as a finished formula hasn't been independently researched. You're evaluating based on ingredient-level evidence, which isn't the same as product-level proof.
Individual responses vary considerably: Some people respond well to BHB supplementation; others don't. There's no reliable way to predict your response before trying.
It doesn't work in isolation: If you're hoping for changes without attention to diet, activity, sleep, and stress, adjusting expectations is important. This applies to all supplements.
This category is still evolving: The exogenous ketone space has less research than many other supplement categories, and weight-specific outcomes are not established.
The Honest Summary
LeptiThin Max may be worth considering for people who:
Want to explore ketone supplementation without strict dietary restriction
Are combining supplementation with genuine lifestyle attention
Have realistic expectations about what supplements can and cannot do
Are healthy adults without contraindications
Will commit to adequate evaluation time
It may not be appropriate for people:
Expecting significant changes without other attention
With health conditions requiring medical supervision
Seeking prescription-level interventions
Looking for shortcuts
If you decide to try it, approach with clear expectations: this is a supplement that raises blood ketone levels and may be worth exploring for some people during dietary transitions (for example, energy or appetite experiences), but outcomes vary widely. The only way to know your response is to try it, track your experience honestly, and make an informed decision based on what you actually observe.
Your path forward is yours to choose. A supplement might be part of it. But you're the one making the choices that matter most.
See current LeptiThin Max offer (verify pricing at checkout)
Part 12: Contact Information
For questions before or during your order, according to the company's official contact page:
Company: LeptiThin Max
Product Support Email: [email protected]
Phone: 307-223-2329
Hours: 9am-5pm EST, Monday through Friday
Order Support: Available through BuyGoods order lookup at buygoods.com/orderlookup
Disclaimers
FDA Health Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your physician before starting any new supplement, especially if you have existing health conditions, take medications, or are pregnant or nursing.
Professional Medical Disclaimer: This article is educational and does not constitute medical advice. LeptiThin Max is a dietary supplement, not a medication. If you are currently taking medications, have existing health conditions, are pregnant or nursing, or are considering any major changes to your health regimen, consult your physician before starting LeptiThin Max or any new supplement. Do not change, adjust, or discontinue any medications or prescribed treatments without your physician's guidance and approval.
Individual Results Disclosure: Individual responses to dietary supplements vary based on factors including age, baseline health, dietary habits, activity levels, consistency of use, genetic factors, medications, and other variables. Some users report positive experiences; others notice no difference. Results are not guaranteed. Weight outcomes are not established for this finished product. The information presented reflects ingredient-level research and general patterns, not predictions about specific outcomes.
FTC Affiliate Disclosure: This article contains affiliate links. If you purchase through these links, a commission may be earned at no additional cost to you. This compensation does not influence the information presented. All descriptions are based on publicly available information.
Pricing Disclaimer: Pricing information was based on the official website at time of publication (January 2026) and is subject to change. Always verify current pricing and terms on the official LeptiThin Max website before purchasing.
Publisher Responsibility Disclaimer: The publisher has made reasonable efforts to ensure accuracy at time of publication based on publicly available information. We do not accept responsibility for errors, omissions, or outcomes resulting from the use of information provided. Verify details directly with LeptiThin Max and your healthcare provider before making decisions.
Ingredient Interaction Notice: BHB supplements contain electrolytes (sodium, magnesium, calcium) that may interact with certain medications or affect people with specific health conditions. People with kidney concerns, heart conditions, blood pressure issues, diabetes, or those taking diuretics, blood pressure medications, or other electrolyte-affecting medications should consult their healthcare provider before use.
SOURCE: LeptiThin Max
Source: LeptiThin Max
Share:
Tags: Consumer guidance, Dietary supplements, Exogenous ketones, Ingredient research, Ketogenic diet