Keto, Paleo, Primal, Vegan, Intermittent Fasting, which diet should I follow?

If you are paying any attention to current diet trends, you’ve likely heard ofsalad the diets above. I often get the question “What do you think of keto” when I’m giving talks, and inevitably I am mostly through the answer (and sometimes putting my foot in my mouth) when I think to ask “Are you on keto now?” They always are. 😃

Here’s a brief synopsis of each diet for those who are unfamiliar.

Vegan: No meat, eggs, or dairy products (cheese, milk, etc.)

Ketogenic: 70-80% daily calories from fat, 5-10% from carbohydrates, and 10-20% from protein (so effectively, no grains, only low sugar fruit and non-starchy vegetables, no legumes, no added sugar). Monitoring of urine to check for ketones, indicating your body is burning fat as a fuel vs. glucose.

Paleo: Only food that would have been available to our paleolithic ancestors. No dairy, no grains, no legumes (including soy and peanuts), no processed food (so no added sugars, seed oils, etc.), discourages nightshade vegetables (tomatoes, eggplant, potatoes, peppers) and coffee. Natural, unprocessed sweeteners like honey and maple syrup are allowed.

Primal: Like paleo but allows raw dairy products, nightshades and coffee.

Intermittent Fasting: Limiting eating to 8-10 hours/day; eating normally 5 days a week and having 500-600 calories 2 days a week; or fasting entirely for 1-4 days/week.

Since I help clients with weight loss, people are often asking my opinion of these diets in that context. My first question to them is: “Is it sustainable? Are you prepared to eat this way for the rest of your life?” Because I don’t put my clients on diets. I teach them how to eat for the rest of their lives so as to break insulin resistance, lose weight, keep it off and be in your best health. 95% of people who diet gain the weight back within 3 years. The above “diets” are meant to be lifestyles, not diets. While they all have the potential to trigger weight loss (especially the last four) because they generally lead to lower consumption of added sugars and processed starches or calories in general, they are also difficult to sustain because they eliminate foods that are common in the American diet and in some cases, very nutritious foods. And for totally grain-free and very low carbohydrate diets like the ketogenic diet, I have concerns about the impact on the gut microbiome, which is a topic that scientific research has yet to settle. And any diet that eliminates entire food groups could lead to nutritional deficiencies if used long term.

In my personal experience, I have tried super low fat/low carb diets and intermittent fasting. While both led to weight loss, neither was sustainable for me. I thought about food constantly and felt totally hungry and deprived. And when I went off of them, the weight came back on quickly. However, eliminating sugar and most white wheat-based flours (I do eat gluten-free flours) and keeping grains reasonable (generally 1 serving/meal + 1-2/day as snacks) has allowed me to keep weight off. However, I recognize that some people’s bodies are not able to eat even that quantity of carbohydrates and maintain weight. A recent study showed that only about half of us have a gene mutation that allows our bodies to cope with high glucose diets. So if you’ve been struggling to lose weight and keep it off, I’d suggest looking at your consumption of sugar and grains (bread, pasta, chips, rice, desserts, etc.) and trying to reduce as much as possible until the weight starts to come off. Then when you get to your ideal weight, add grains back in slowly until you are safely maintaining your weight. Desserts with added (or concentrated natural) sugar should remain an occasional treat.