Previous month I attended a “Diet Discussion,” in which speakers argued for several approaches, such as Mediterranean, ketogenic, and intermittent fasting.
The speaker defending the ketogenic food plan described many individuals in his clinic who experienced misplaced a great offer of body weight and knowledgeable advancements in measures of heart failure. Compelling tales for sure.
But as promising as these types of situation reports can be, they are regarded as one particular of the least specific types of scientific evidence, since bias and elements other than the diet program can affect the success.
Plus, in any fat decline research, persons reduce vastly diverse quantities of bodyweight. Some eliminate a lot more, some less, some attain bodyweight! Envision if you just talked to the couple of who missing extra and drew conclusions from just them.
A person recent review evaluating a lower-carbohydrate to a lower-fats bodyweight decline diet program experienced contributors who misplaced up to 72 kilos and some who gained up to 24 kilos! (Neither method came out in advance all round. See Figure 2 here.) Other experiments (here and here) have claimed equivalent results.
If that is a weight loss clinic as an alternative of medical exploration, guess which clients will develop into the circumstance studies? Who do you believe seems in their ads? Who do you imagine begins a web site or writes a e book?
The problem we must inquire is: “If a substantial group of individuals are randomly assigned to stick to one particular dietary approach or a further, preferably for a calendar year or more, how does every group do?” That decreases the prospect that other things push the effects.
These scientific studies are extra tough and highly-priced to do, so we really don’t have all the responses. But let’s choose a glance at what we know so far for these three approaches.
Mediterranean
What is it?
Rich in complete plant foodstuff: veggies, fruit, entire grains, legumes, nuts, olive oil as properly as fish. Some poultry, eggs, and dairy. Confined red meat and sweets. Red wine with foods in moderation if wished-for.
Outcomes evidence
(For illustration, do folks have fewer coronary heart activities? Do they live longer, much healthier lives?)
The Mediterranean feeding on pattern has been revealed to lessen risk of over-all mortality, cardiovascular conditions, coronary heart condition, coronary heart attacks, all round cancer incidence, neurodegenerative illnesses and type 2 diabetes. (See also Becerra-Tomás 2020.)
This is centered on substantial proof which includes randomized controlled trials, which are deemed higher quality. For this explanation most cardiac guidelines recommend Mediterranean-fashion feeding on.
Improvements in heart ailment risk aspects
(People today assume these will have equivalent impacts on coronary heart results, whilst that is not normally the scenario! They are, on the other hand, a lot easier to study.)
Scientific studies have revealed improvements in blood sugar management, HDL-cholesterol and triglycerides (TG). There is commonly very little result on body pounds or waist circumference.
Some studies exhibit a modest reduction in blood stress and LDL-cholesterol.
Pros
This way of feeding on is flexible, nutrient-dense, and less difficult for persons who delight in plant-primarily based meals. Plus those lengthy-phrase wellness results are very desirable.
Cons
Some men and women choose extra framework. Also, some will be upset that sizeable weight reduction is not common with this method.
There is also a problem with cultural stigma – the implication that food items from this location is superior to other worldwide cuisines, which have not been as extensively analyzed. On the other hand, comparable eating designs with common foodstuff from other components of the earth are very likely to be similarly helpful.
The Mediterranean solution may possibly involve far more arranging, prepping, and kitchen area techniques.
Ketogenic
What is it?
Very low in carbohydrates and large in unwanted fat with reasonable protein, these types of as the Atkins diet regime. At times less arduous reduced-carbohydrate diets are inaccurately explained as ketogenic.
In follow, that means you consume a great deal of meat, fish, poultry, eggs, some cheese, and fat. Minimal vegetables, no grains or starches, no fruit, milk, yogurt or sweets.
Outcomes evidence
Rates of cardiovascular condition, other diabetes issues, or mortality are not known, at least from significant top quality scientific tests.
Reduced carbohydrate eating plans in common have been located to be linked with a larger danger of mortality in observational scientific studies, but these are viewed as a weak type of proof.
Adjustments in heart sickness threat factors
Greater bodyweight decline in the shorter term (<6 months) relative to control diets. Comparable weight loss in studies lasting longer than 6 months (both from Kirkpatrick 2019).
Improvements in blood sugar control, although not clearly superior to more balanced diets in the long run.
A decrease in triglycerides is usually seen. Effect on LDL-cholesterol is variable.
Some evidence of diabetes remission, but a Diabetes Canada steering committee chose not to include this approach in their 2022 Special Article on Remission of Type 2 Diabetes, because studies did not meet the criteria for remission or level of evidence.
Pros
Easier for meat-lovers. Simple.
Cons
Lack of research into long-term health impacts.
Limited food choices. Generally difficult to sustain, although some may prefer it.
Low in fibre. Low in some vitamins, minerals, and other nutrients. May be high in sodium if processed meat is used extensively.
Weight loss appears to include greater loss of lean body mass compared with more macronutrient balanced diets.
Was associated with higher risk of atrial fibrillation, although this study allowed more carbohydrate than the more strict ketogenic diet.
Adverse effects reported include constipation, diarrhea, headache, halitosis, muscle cramps, general weakness and rash.
Some experience “keto flu” during the first week or so: “lightheadedness, dizziness, fatigue, difficulty exercising, poor sleep, and constipation.”
Higher food costs than diets incorporating more carbohydrate.
Concerns about environmental sustainability of diets high in animal protein.
Notes
Certain medications may need to be adjusted due to rapid weight changes. Avoid with certain diabetes medications. Check with your doctor.
Not advised in patients with a history of pancreatitis, severe hypertriglyceridemia, or inherited causes of severe hypercholesterolemia. Safety not established during pregnancy. Check with your doctor.
Intermittent Fasting (IF)
What is it?
People practice and study several different approaches to intermittent fasting:
- Time-restricted feeding (TRF): Eating only during a 6-12 hour period during the day. (For example 12pm to 8pm.)
- Alternate day fasting: Fasting (fully or partially) every other day and eating as you like on the alternate days.
- 5:2: Fasting (fully or partially) two days a week and eating as you like on the other five days.
The choice of foods is not considered in this approach, although IF is sometimes combined with other eating patterns.
Outcomes evidence
No high quality studies were found that assessed all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, or heart failure.
Two observational cohort studies found that fasting was associated with a lower prevalence of coronary artery diseases or diabetes but again, these are considered a weak form of evidence (see also Horne 2008).
Changes in heart disease risk factors
More weight loss than doing nothing, although not always clinically significant amounts (See also Welton 2020 and Harris 2018).
Interestingly, in one study, TRF did not produce more weight loss than participants instructed to eat 3 structured meals per day.
Typically studies find similar weight loss to low-calorie diets (See also Welton 2020, Harris 2018, Cioffi 2018).
Some degree of weight regain was seen in most studies after 6-12 months, similar to low-calorie diets.
Pros
Simple rules. No foods restricted.
Cons
Lack of research into long-term health impacts. Few studies longer than 24 weeks (See also Headland 2019). However, plenty of research is underway, so stay tuned.
Adverse effects cited by some participants (<20%) include lack of energy, headaches, feeling cold, constipation, bad breath, lack of concentration, and bad temper.
One recent study found a greater loss of lean body (muscle) mass in the TRF group, as well as a decrease in physical activity.
High dropout rates (≥ 25%) in several IF studies, which compare poorly to the 12% to 14% dropout rates of other long-term diets.
Limited evidence suggests that participants randomized to IF in studies report lower quality of life scores compared to energy-restricted dieting.
Notes
Limited evidence in people living with heart disease.
Not recommended for people:
- With a history of eating disorders or disordered eating
- At risk for loss of muscle mass and strength (eg. people with cancer)
- At risk for low blood sugars
The bottom line
Given the current state of the research, we have a choice between the Mediterranean eating pattern, which has been shown to improve your chances of a longer, healthier life, or IF or keto, which may result in at least short-term weight loss and blood sugar control.
People assume that weight loss will lead to better long-term health outcomes, but evidence of that is still sorely lacking.
If weight loss is important to you, the ketogenic and IF approaches may be understandably compelling, but I hesitate to recommend them, because frustratingly, people so often regain the weight.
The other question to consider is “Which way of eating feels like a good fit for you?” Choosing an approach that you enjoy and can see yourself eating long-term is critical.
I hope that brings some clarity to the conversations and explorations you might be having at this time of year.
Personally I don’t like to set people up for failure, and I feel we should focus on proven health outcomes, so I generally recommend Mediterranean-style eating, but the choice is clearly yours.
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