Say No To Keto
Keto diet – high in fat, low in evidence.
The keto diet claims to help with weight loss, athletic performance, energy levels, appetite control, cholesterol reduction, and stabilisation of blood sugar levels, however, in general the benefits are exaggerated, risks are downplayed, and science takes a back seat to marketing.
Most of the time it’s not healthy or sustainable - in my opinion it’s a short term solution that will not fix a long term problem. It’s not a forever diet, it’s a passing trend - there will be life after keto!
What is it?
A high fat, low carb diet that promises to turn your body into a fat burning machine. By depleting your body of carbohydrates, it’s major energy source, it’s forced to burn fat for fuel. Fat is broken down in the liver, producing ketones, which are used to fuel the body in place of glucose (which is the product of carbohydrate breakdown). This sends you into a state of ketosis within 2-3 days. This process can happen when fasting, after prolonged exercise, during starvation, or when eating a low-carb, ketogenic diet. Staying in ketosis requires strict monitoring of carbohydrate intake, even a serving of blueberries will revert your body to carbohydrate burning. Therefore a lot of people doing the keto diet do not actually stay in ketosis, and how would you know anyway? Most people do not monitor their blood, urine or breath ketone levels.
What do you eat?
Carbohydrate intake on the keto diet is usually around 5% of food intake (compared to the typical NZ diet of around 50-65%), with fat making up the majority of the diet accompanied by moderate amounts of protein.
Foods you can eat on a keto diet: oils, avocado, cream, butter, cheese, nuts, non-starchy veges (eg. cucumber, spinach, broccoli), meat, eggs, and fatty fish.
Foods you avoid on a keto diet: most fruit (except a small portion of berries), root veges and tubers (potatoes, kumara, carrots, parsnips, corn etc), beans and legumes, wholegrains and starches (bread, rice, pasta, cereal), milk, desserts and baked goods. Therefore if not done well, you can end up eating a lot of nutrient poor foods!
Why do the keto diet?
The main reason people do the keto diet is for weight loss. People usually lose a lot of weight fast but the weight that’s lost initially is water, due to severely cutting down on carb intake (as carbs retain fluid). Most people continue to lose weight because they’ve suddenly stopped having fizzy drink, cakes, burgers, potato chips and other unhealthy foods. Other reasons for weight loss include: severely restricting food choices tends to result in fewer calories being consumed; the reduction in sugar and refined carbohydrates leads to more stable blood sugar levels (and more stable energy levels); potentially reduced hunger due to the satiety effect of proteins helping you feel fuller for longer; some potential positive effects on appetite hormones; the fact that it takes more energy to burn fat than carbs; and the keto diet resulting in lower insulin levels which increases burning of stored fat in the body (if you don’t overeat).
On the plus side you’ll be avoiding the generally over-consumed highly refined carbohydrates, but there’s no benefit if these are mainly replaced by bacon, cream and butter. It’s important to remember that the calories in fat are still calories, so keeping total intake at a reasonable level is the only way it works.
What’s the science?
Most studies of the keto diet are in rats or very small populations of humans. The only clear and proven health benefit of the keto diet is reducing epileptic seizures in children (the keto diet has been used for this since the 1920’s).
There is no shortage of short-term weight loss success stories, however, there is limited evidence to show the weight is kept off in the long term, or that in the long term it is any more effective than other popular diets.
The keto diet may also help improve energy levels or athletic performance and assist glycemic control in diabetes (however these people are at higher risk of cardiovascular disease so the high fat intake is of concern and so is the low fibre intake, due to restricted fruit and veges, which is known to help diabetes management).
Distinct downsides!
Weight becomes the sole determinant of health and is pursued at any cost:
1. Due to eliminating certain food groups (most dairy, fruit, legumes, wholegrains, some veges), potential risks are vitamin and mineral deficiencies, kidney stones, gastrointestinal distress (eg. constipation through a lack of fibre), and decreased bone mineral density (increasing calcium loss).
2. Low fruit and vege intake is also of concern as these foods are known to assist prevention of chronic diseases and contain many micronutrients all with a variety of health benefits.
3. The diet generally ends up being low in fibre which is known to be very important for gut health, lowering risk of chronic diseases, and maintaining a healthy weight.
4. While some fats are healthy there are concerns about the high saturated fat content of this diet in relation to cholesterol levels and heart disease.
5. Long term safety is unknown.
6. Keto-flu is a common side effect initially (headache, fatigue) due to losing a lot of water weight which can lead to dehydration.
7. Following a keto diet is hard! You have to be disciplined and super aware of everything you eat. It becomes very difficult to stick to because it is highly restrictive - some studies have shown only a 40-50% compliance rate.
8. Socially awkward – not easy to go out and be sure the food you eat is 100% keto friendly.
9. It can be done very unhealthily if you are only eating processed high fat foods and not having any fresh, minimally processed, highly nutritious foods.
10. The keto diet doesn’t teach about lifestyle habits – weight is often regained once off the diet.
Bottom line
Diets that eliminate entire food groups are a red flag! It may lead to short term weight loss but it is difficult to follow, lacks nutrition and has potential health risks from cutting out major food groups and increasing saturated fat intake. At best, if managed carefully, it is a short term diet however it does not teach habits that create a long term healthy lifestyle.
References
https://www.ncbi.nlm.nih.gov/books/NBK493179/
https://www.ncbi.nlm.nih.gov/pubmed/25402637
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4302176/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945587/
https://www.ncbi.nlm.nih.gov/pubmed/17332207
https://www.dietdoctor.com/low-carb/keto
https://jamanetwork.com/journals/jama/article-abstract/2673150